Fernando Lledó, Carlos Palazuelos, and Julio I. de Vicente,

Quantum 9, 1958 (2025).

Quantum networks are promising venues for quantum information processing. This motivates the study of the entanglement properties of the particular multipartite quantum states that underpin…

Beatrice Magni and Xhek Turkeshi,

Quantum 9, 1956 (2025).

We investigate the emergence of quantum complexity and chaos in doped Clifford circuits acting on qudits of odd prime dimension $d$. Using doped Clifford Weingarten calculus and a replica tens…

Yudai Suzuki, Bi Hong Tiang, Jeongrak Son, Nelly H. Y. Ng, Zoe Holmes, and Marek Gluza,

Quantum 9, 1954 (2025).

Quantum Signal Processing (QSP), a framework for implementing matrix-valued polynomials, is a fundamental primitive in various quantum algorithms. Despite its versatility, a potentially unde…

William A. Simon, Carter M. Gustin, Kamil Serafin, Alexis Ralli, Gary R. Goldstein, and Peter J. Love,

Quantum 9, 1953 (2025).

We describe and analyze LOBE (Ladder Operator Block-Encoding), a framework for block-encoding ladder operators that act upon fermionic and bosonic modes. In this framework, we achieve effici…

Christina Giarmatzi, Tyler Jones, Alexei Gilchrist, Prasanna Pakkiam, Arkady Fedorov, and Fabio Costa,

Quantum 9, 1952 (2025).

Current quantum technologies are at the cusp of becoming useful, but still face formidable obstacles such as noise. Noise severely limits the ability to scale quantum devices to the point th…

Diego Forlivesi, Lorenzo Valentini, and Marco Chiani,

Quantum 9, 1950 (2025).

We analyze the performance of quantum stabilizer codes, one of the most important classes for practical implementations, on both symmetric and asymmetric quantum channels. To this aim, we fi…

Gabriel O. Alves, Felix Fritzsch, and Pieter W. Claeys,

Quantum 9, 1949 (2025).

The eigenstate thermalization hypothesis (ETH) is the leading interpretation in our current understanding of quantum thermalization. Recent results uncovered strong connections between quant…

Xiangyi Meng, Nicolò Lo Piparo, Kae Nemoto, and István A. Kovács,

Quantum 9, 1948 (2025).

Building large-scale quantum communication networks has its unique challenges. Here, we demonstrate that a network-wide synergistic usage of quantum memories distributed in a quantum communi…

Abhishek Chakraborty, Taylor L. Patti, Brucek Khailany, Andrew N. Jordan, and Anima Anandkumar,

Quantum 9, 1946 (2025).

Effective Hamiltonian calculations for large quantum systems can be both analytically intractable and numerically expensive using standard techniques. In this manuscript, we present numerica…

Shishir Khandelwal and Gianmichele Blasi,

Quantum 9, 1944 (2025).

Recent years have seen a surge of interest in exceptional points in open quantum systems. The natural approach in this area has been the use of Markovian master equations. While the resultin…

Boris Bourdoncle, Pierre-Emmanuel Emeriau, Paul Hilaire, Shane Mansfield, Luka Music, and Stephen Wein,

Quantum 9, 1943 (2025).

Secure Delegated Quantum Computation (SDQC) protocols are a vital piece of the future quantum information processing global architecture since they allow end-users to perform their valuable…

Chenfeng Cao, Yeqing Zhou, Swamit Tannu, Nic Shannon, and Robert Joynt,

Quantum 9, 1942 (2025).

Variational quantum algorithms (VQAs) represent a promising pathway toward achieving practical quantum advantage on near-term hardware. Despite this promise, for generic, expressive ansätze,…

X. T. Yan, S. Kannan, Y. S. Athreya, A. G. Truscott, and S. S. Hodgman,

Quantum 9, 1939 (2025).

We propose a Bell test experiment using momentum-entangled atom pairs of different masses, specifically metastable helium isotopes ${}^{3}He^{*}$ and ${}^{4}He^{*}$, though the method extends to…

Dripto M. Debroy, Matt McEwen, Craig Gidney, Noah Shutty, and Adam Zalcman,

Quantum 9, 1936 (2025).

Recently, usage of detecting regions facilitated the discovery of new circuits for fault-tolerantly implementing the surface code. Building on these ideas, we present LUCI, a framework for c…

Shiran Even-Haim, Asaf A. Diringer, Ron Ruimy, Gefen Baranes, Alexey Gorlach, Shay Hacohen-Gourgy, and Ido Kaminer,

Quantum 9, 1934 (2025).

Conditional displacement with a qubit ancilla is a critical component in continuous-variable error correction protocols. We present the generalized conditional displacement operator, conditi…

Jan Perina Jr, Kishore Thapliyal, Grzegorz Chimczak, Anna Kowalewska-Kudlaszyk, and Adam Miranowicz,

Quantum 9, 1933 (2025).

We analyze the existence and degeneracies of quantum exceptional, diabolical, and hybrid points in simple bosonic systems – comprising up to six modes with damping and/or amplification – und…

Kishore Thapliyal, Jan Perina Jr., Grzegorz Chimczak, Anna Kowalewska-Kudlaszyk, and Adam Miranowicz,

Quantum 9, 1932 (2025).

The existence and degeneracies of quantum exceptional, diabolical, and hybrid (i.e., diabolically degenerated exceptional) singularities of simple bosonic systems composed of up to five mode…

Mingyu Kang, Yingjia Lin, Hanwen Yao, Mert Gökduman, Arianna Meinking, and Kenneth R. Brown,

Quantum 9, 1931 (2025).

To achieve quantum fault tolerance with lower overhead, quantum low-density parity-check (QLDPC) codes have emerged as a promising alternative to topological codes such as the surface code,…

Lewis Wooltorton, Peter Brown, and Roger Colbeck,

Quantum 9, 1930 (2025).

Nonlocal tests on multi-partite quantum correlations form the basis of protocols that certify randomness in a device-independent (DI) way. Such correlations admit a rich structure, making th…

Marit O. E. Steiner, Julen S. Pedernales, and Martin B. Plenio,

Quantum 9, 1928 (2025).

We explore the potential of levitating solids embedded with non-permanent, optically controllable electron spins, which can be used to hyperpolarize their nuclear spin environment with excep…

Matthew Amy and Lucas Shigeru Stinchcombe,

Quantum 9, 1926 (2025).

Implementations of Roetteler's shifted bent function algorithm have in recent years been used to test and benchmark both classical simulation algorithms and quantum hardware. These circuits…

Ben Zindorf and Sougato Bose,

Quantum 9, 1925 (2025).

Universal gate sets for quantum computation, when single and two qubit operations are accessible, include both Hermitian and non-Hermitian gates. Here we utilize the fact that any single-qub…

Cahit Kargi, Angsar Manatuly, Lukas M. Sieberer, Juan Pablo Dehollain, Fabio Henriques, Tobias Olsacher, Philipp Hauke, Markus Heyl, Peter Zoller, and Nathan K. Langford,

Quantum 9, 1924 (2025).

Digital quantum simulation (DQS) is one of the most promising paths for achieving first useful real-world applications for quantum processors. Yet even assuming rapid progress in device engi…

Augustin Vanrietvelde, Nick Ormrod, Hlér Kristjánsson, and Jonathan Barrett,

Quantum 9, 1923 (2025).

Over the past decade, a number of quantum processes have been proposed which are logically consistent, yet feature a cyclic causal structure. However, there is no general formal method to co…

Min Ye and Nicolas Delfosse,

Quantum 9, 1920 (2025).

We propose a model for quantum computing with long chains of trapped ions and we design quantum error correction schemes for this model. The main components of a quantum error correction sch…

Felix Huber and Nikolai Wyderka,

Quantum 9, 1918 (2025).

The spectral variant of the quantum marginal problem asks: Given prescribed spectra for a set of overlapping quantum marginals, does there exist a compatible joint state? The main idea of th…

Zuzana Gavorová,

Quantum 9, 1916 (2025).

To better understand quantum computation we can search for its limits or no-gos, especially if analogous limits do not appear in classical computation. Classical computation easily implement…

Samo Novák, David D. Roberts, Alexander Makarovskiy, Raúl García-Patrón, and William R. Clements,

Quantum 9, 1915 (2025).

Loop-based boson samplers interfere photons in the time degree of freedom using a sequence of delay lines. Since they require few hardware components while also allowing for long-range entan…

Daniel McNulty, Susane Calegari, and Michał Oszmaniec,

Quantum 9, 1914 (2025).

An important class of fermionic observables, relevant in tasks such as fermionic partial tomography and estimating energy levels of chemical Hamiltonians, are the binary measurements obtaine…

Jeet Shah, Christopher Fechisin, Yu-Xin Wang, Joseph T. Iosue, James D. Watson, Yan-Qi Wang, Brayden Ware, Alexey V. Gorshkov, and Cheng-Ju Lin,

Quantum 9, 1912 (2025).

Recent experimental progress in controlling open quantum systems enables the pursuit of mixed-state nonequilibrium quantum phases. We investigate whether open quantum systems hosting mixed-s…

Aniruddha Sen, Kenneth Goodenough, and Don Towsley,

Quantum 9, 1911 (2025).

Quantum networks are important for quantum communication, enabling tasks such as quantum teleportation, quantum key distribution, quantum sensing, and quantum error correction, often utilizi…

Pegah Mohammadipour and Xiantao Li,

Quantum 9, 1909 (2025).

Zero-noise extrapolation (ZNE) is a widely used quantum error mitigation technique that artificially amplifies circuit noise and then extrapolates the results to the noise-free circuit. A co…

Filip B. Maciejewski, Jacob Biamonte, Stuart Hadfield, and Davide Venturelli,

Quantum 9, 1906 (2025).

We present Noise-Directed Adaptive Remapping (NDAR), a heuristic algorithm for approximately solving binary optimization problems by leveraging certain types of noise. We consider access to…

Peter-Jan H.S. Derks, Alex Townsend-Teague, Ansgar G. Burchards, and Jens Eisert,

Quantum 9, 1905 (2025).

Quantum error-correcting codes, such as subspace, subsystem, and Floquet codes, are typically constructed within the stabilizer formalism, which does not fully capture the idea of fault tole…

Tom Krüger and Wolfgang Mauerer,

Quantum 9, 1903 (2025).

The Quantum Approximate Optimisation Algorithm (QAOA) is a widely studied quantum-classical iterative heuristic for combinatorial optimisation. While QAOA targets problems in complexity clas…

Yujie Zhang, Jiaxuan Zhang, and Eric Chitambar,

Quantum 9, 1902 (2025).

Quantum entanglement is a fundamental feature of quantum mechanics, yet certain entangled states that are unsteerable can be classically simulated in steering scenarios, making them unable t…

Maarten Stroeks and Barbara M. Terhal,

Quantum 9, 1900 (2025).

We introduce the fermionic satisfiability problem, Fermionic $k$-SAT: this is the problem of deciding whether there is a fermionic state in the null-space of a collection of fermionic, parity-…

Ansgar G. Burchards, Steven T. Flammia, and Jonathan Conrad,

Quantum 9, 1899 (2025).

We investigate multi-mode GKP (Gottesman–Kitaev–Preskill) quantum error-correcting codes from a geometric perspective. First, we construct their moduli space as a quotient of groups and exhi…

Sebastian Schulz, Dennis Willsch, and Kristel Michielsen,

Quantum 9, 1898 (2025).

We present Learning-Driven Annealing (LDA), a framework that links individual quantum annealing evolutions into a global solution strategy to mitigate hardware constraints such as short anne…

Shalin Jose, Akshay Kannan Sairam, and Anil Shaji,

Quantum 9, 1895 (2025).

A path for efficient classical simulation of the DQC1 circuit that estimates the trace of an implementable unitary under the zero discord condition [17] is presented. This result reinforces…

Younghun Kim, Hansol Kim, Jeongsoo Kang, Wonjae Choi, and Younghun Kwon,

Quantum 9, 1893 (2025).

Large-scale quantum circuits are required to exploit the advantages of quantum computers. Despite significant advancements in quantum hardware, scalability remains a challenge, with errors a…

Elisabeth Wybo and Martin Leib,

Quantum 9, 1892 (2025).

We consider the maximum cut and maximum independent set problems on random regular graphs in the infinite-size limit, and calculate the energy densities achieved by QAOA for high degrees up…

Owen C. Wetherbee, Saswata Roy, Baptiste Royer, and Valla Fatemi,

Quantum 9, 1890 (2025).

Bosonic encodings of quantum information offer hardware-efficient, noise-biased approaches to quantum error correction relative to qubit register encodings. Implementations have focused in p…

Alexey Milekhin and Sara Murciano,

Quantum 9, 1888 (2025).

Measurements in many-body quantum systems can generate non-trivial phenomena, such as preparation of long-range entangled states, dynamical phase transitions, or measurement-altered critical…

Pedro C.S. Costa, Dong An, Ryan Babbush, and Dominic Berry,

Quantum 9, 1887 (2025).

The solution of linear systems of equations is the basis of many other quantum algorithms, and recent results provided an algorithm with optimal scaling in both the condition number $\kappa$ a…

Esther Xiaozhen Fu and Daniel Gottesman,

Quantum 9, 1886 (2025).

We ask what is the general framework for a quantum error correcting code that is defined by a sequence of measurements. Recently, there has been much interest in Floquet codes and space-time…

Alexander Nietner, Marios Ioannou, Ryan Sweke, Richard Kueng, Jens Eisert, Marcel Hinsche, and Jonas Haferkamp,

Quantum 9, 1883 (2025).

In this work, we show that learning the output distributions of brickwork random quantum circuits is average-case hard in the statistical query model. This learning model is widely used as a…

Gereon Koßmann, Lennart Binkowski, Lauritz van Luijk, Timo Ziegler, and René Schwonnek,

Quantum 9, 1882 (2025).

Despite its popularity, several empirical and theoretical studies suggest that the quantum approximate optimization algorithm (QAOA) has persistent issues in providing a substantial practica…

David Schmid, John H. Selby, Vinicius P. Rossi, Roberto D. Baldijão, and Ana Belén Sainz,

Quantum 9, 1880 (2025).

It is commonly believed that failures of tomographic completeness undermine assessments of nonclassicality in noncontextuality experiments. In this work, we study how such failures can indee…

José A. Almanza-Marrero and Gonzalo Manzano,

Quantum 9, 1878 (2025).

Quantum coherence has been shown to impact the operational capabilities of quantum systems performing thermodynamic tasks in a significant way, and yet the possibility and conditions for gen…

Samuel Fedida, Anne-Catherine de la Hamette, Viktoria Kabel, and Časlav Brukner,

Quantum 9, 1875 (2025).

We explore indefinite causal order between events in the context of quasiclassical spacetimes in superposition. We introduce several new quantifiers to measure the degree of indefiniteness o…

Joseph Bowles, David Wierichs, and Chae-Yeun Park,

Quantum 9, 1873 (2025).

The discovery of the backpropagation algorithm ranks among one of the most important moments in the history of machine learning, and has made possible the training of large-scale neural netw…

Vaibhav Sharma and Kaden R. A. Hazzard,

Quantum 9, 1872 (2025).

Quantum simulation of lattice gauge theories is an important avenue to gain insights into both particle physics phenomena and constrained quantum many-body dynamics. There is a growing inter…

Martina Gisti, David J. Luitz, and Maxime Debertolis,

Quantum 9, 1871 (2025).

We extend the concept of operator charge in the context of an abelian $U(1)$ symmetry and apply this framework to symmetry-preserving matrix product operators (MPOs), enabling the description…

Khurshed P. Fitter, Cécilia Lancien, and Ion Nechita,

Quantum 9, 1870 (2025).

Genuine multipartite entanglement of a given multipartite pure quantum state can be quantified through its geometric measure of entanglement, which, up to logarithms, is simply the maximum o…

Luis A. Correa and Jonas Glatthard,

Quantum 9, 1868 (2025).

Often, the microscopic interaction mechanism of an open quantum system gives rise to a `counter term' which renormalises the system Hamiltonian. Such term compensates for the distortion of t…

Aritra Das, Lorcán O. Conlon, Jun Suzuki, Simon K. Yung, Ping K. Lam, and Syed M. Assad,

Quantum 9, 1867 (2025).

In multi-parameter quantum metrology, the resource of entanglement can lead to an increase in efficiency of the estimation process. Entanglement can be used in the state preparation stage, o…

Alberto Mercurio, Yi-Te Huang, Li-Xun Cai, Yueh-Nan Chen, Vincenzo Savona, and Franco Nori,

Quantum 9, 1866 (2025).

We present $\tt{QuantumToolbox.jl}$, an open-source Julia package for simulating open quantum systems. Designed with a syntax familiar to users of $\tt{QuTiP}$ (Quantum Toolbox in Python), it ha…

Zhiyao Li, Dorota M. Grabowska, and Martin J. Savage,

Quantum 9, 1865 (2025).

We introduce the Sequency Hierarchy Truncation (SeqHT) scheme for reducing the resources required for state preparation and time evolution in quantum simulations, based upon a truncation in…

A. Keefe, N. Agarwal, and A. Kamal,

Quantum 9, 1863 (2025).

Memory or time-non-local effects in open quantum dynamics pose theoretical as well as practical challenges in the understanding and control of noisy quantum systems. While there has been a c…

Carlos Vega, Alberto Muñoz de las Heras, Diego Porras, and Alejandro González-Tudela,

Quantum 9, 1861 (2025).

Non-reciprocal couplings or drivings are known to induce steady-state, directional, amplification in driven-dissipative bosonic lattices. This amplification phenomenon has been recently link…

Stefano Carignano and Luca Tagliacozzo,

Quantum 9, 1859 (2025).

We show how the Loschmidt echo of a product state after a quench to a conformal invariant critical point and its leading finite time corrections can be predicted by using conformal field the…

Yunzhe Zheng and Dong E. Liu,

Quantum 9, 1858 (2025).

Magic State Distillation (MSD) has been a research focus for fault-tolerant quantum computing due to the need for non-Clifford resource in gaining quantum advantage. Although many of the MSD…

Jiaqi Leng, Joseph Li, Yuxiang Peng, and Xiaodi Wu,

Quantum 9, 1857 (2025).

Many promising quantum applications depend on the efficient quantum simulation of an exponentially large sparse Hamiltonian, a task known as sparse Hamiltonian simulation, which is fundament…

Alexandra Ramôa and Luis Paulo Santos,

Quantum 9, 1856 (2025).

We present BAE, a problem-tailored and noise-aware Bayesian algorithm for quantum amplitude estimation. In a fault tolerant scenario, BAE is capable of saturating the Heisenberg limit; if de…

Dilip Paneru, Francesco Di Colandrea, Alessio D’Errico, and Ebrahim Karimi,

Quantum 9, 1855 (2025).

Highly correlated biphoton states are powerful resources in quantum optics, both for fundamental tests of the theory and practical applications. In particular, high-dimensional spatial corre…

Keith R. Fratus, Kirsten Bark, Nicolas Vogt, Juha Leppäkangas, Sebastian Zanker, Michael Marthaler, and Jan-Michael Reiner,

Quantum 9, 1854 (2025).

We consider the extent to which a Trotterized time evolution implemented on a quantum computer is altered by the presence of decoherence. Given a specific set of assumptions regarding the ma…

Bram Vancraeynest-De Cuiper and José Garre-Rubio,

Quantum 9, 1852 (2025).

We propose a systematic framework to construct a $(d+1)$-dimensional stabilizer model from an initial generic d-dimensional abelian symmetry. Our approach builds upon the iterative gauging pro…

Juan Ramón Muñoz de Nova and Fernando Sols,

Quantum 9, 1850 (2025).

We study simultaneous symmetry breaking in spontaneous Floquet states, focusing on the specific case of an atomic condensate. We first describe the quantization of the Nambu-Goldstone (NG) m…

Ali Fahimniya, Hossein Dehghani, Kishor Bharti, Sheryl Mathew, Alicia J. Kollár, Alexey V. Gorshkov, and Michael J. Gullans,

Quantum 9, 1849 (2025).

A central goal in quantum error correction is to reduce the overhead of fault-tolerant quantum computing by increasing noise thresholds and reducing the number of physical qubits required to…

Anthony M. Polloreno, Arnaud Carignan-Dugas, Jordan Hines, Robin Blume-Kohout, Kevin Young, and Timothy Proctor,

Quantum 9, 1848 (2025).

Randomized benchmarking (RB) protocols are widely used to measure an average error rate for a set of quantum logic gates. However, the standard version of RB is limited because it only bench…

Hela Mhiri, Leo Monbroussou, Mario Herrero-Gonzalez, Slimane Thabet, Elham Kashefi, and Jonas Landman,

Quantum 9, 1847 (2025).

In this work, we highlight an unforeseen behavior of the expressivity of Parameterized Quantum Circuits (PQCs) for machine learning. A large class of these models, seen as Fourier series who…

Sascha Heußen and Janine Hilder,

Quantum 9, 1846 (2025).

Code switching is an established technique that facilitates a universal set of FT quantum gate operations by combining two QEC codes with complementary sets of gates, which each by themselve…

Chaitanya Gupta and Anthony J. Short,

Quantum 9, 1845 (2025).

We consider introducing the Dirac sea in a quantum cellular automata model of fermions in discrete spacetime which approximates the Dirac equation in the continuum limit. However, if we atte…

Giuseppe Vitagliano, Otfried Gühne, and Géza Tóth,

Quantum 9, 1844 (2025).

Generalizing the well-known spin-squeezing inequalities, we study the relation between squeezing of collective $N$-particle $su(d)$ operators and many-body entanglement geometry in multi-particl…

Eric Brunner, Luuk Coopmans, Gabriel Matos, Matthias Rosenkranz, Frederic Sauvage, and Yuta Kikuchi,

Quantum 9, 1843 (2025).

Building upon recent progress in Lindblad engineering for quantum Gibbs state preparation algorithms, we propose a simplified protocol that is shown to be efficient under the eigenstate ther…

Timon Scheiber, Paul Haubenwallner, and Matthias Heller,

Quantum 9, 1840 (2025).

Quantum error mitigation is regarded as a possible path to near-term quantum utility. The methods under the quantum error mitigation umbrella term, such as probabilistic error cancellation (…

Xiaoyu Liu, Benjamin F. Schiffer, and Jordi Tura,

Quantum 9, 1838 (2025).

Quantum computers are a highly promising tool for efficiently simulating quantum many-body systems. The preparation of their eigenstates is of particular interest and can be addressed, e.g.,…

Olga Leskovjanová and Ladislav Mišta Jr.,

Quantum 9, 1837 (2025).

We derive a set of genuine multi-mode entanglement criteria for second moments of the quadrature operators. The criteria have a common form of the uncertainty relation between sums of varian…

Yizhi Shen, Daan Camps, Aaron Szasz, Siva Darbha, Katherine Klymko, David B. Williams–Young, Norm M. Tubman, and Roel Van Beeumen,

Quantum 9, 1836 (2025).

Ground state energy estimation in physical, chemical, and materials sciences is one of the most promising applications of quantum computing. In this work, we introduce a new hybrid approach…

Federico Girotti, Alfred Godley, and Madalin Guta,

Quantum 9, 1835 (2025).

We propose a two step strategy for estimating one-dimensional dynamical parameters of a quantum Markov chain, which involves quantum post-processing the output using a coherent quantum absor…

John M. Martyn, Zane M. Rossi, Kevin Z. Cheng, Yuan Liu, and Isaac L. Chuang,

Quantum 9, 1834 (2025).

Quantum signal processing (QSP) is a methodology for constructing polynomial transformations of a linear operator encoded in a unitary. Applied to an encoding of a state $\rho$, QSP enables th…

Isabel Nha Minh Le, Shuo Sun, and Christian B. Mendl,

Quantum 9, 1833 (2025).

We significantly enhance the simulation accuracy of initial Trotter circuits for Hamiltonian simulation of quantum systems by integrating first-order Riemannian optimization with tensor netw…

Myeongjin Shin, Junseo Lee, Seungwoo Lee, and Kabgyun Jeong,

Quantum 9, 1832 (2025).

Estimating the trace of quantum state powers, $\text{Tr}(\rho^k)$, for $k$ identical quantum states is a fundamental task with numerous applications in quantum information processing, including…

Zijian Song and Guanyu Zhu,

Quantum 9, 1831 (2025).

We investigate boundaries of 3D color codes and provide a systematic classification into 101 distinct boundary types, including two novel classes. The first class consists of 1 boundary and…

Edwin Tham and Nicolas Delfosse,

Quantum 9, 1829 (2025).

We propose several optimizations of the CliNR partial error correction scheme which implements Clifford circuits by consuming a resource state. Errors are corrected by measuring a sequence o…

John van de Wetering, Richie Yeung, Tuomas Laakkonen, and Aleks Kissinger,

Quantum 9, 1828 (2025).

Parametrised quantum circuits contain phase gates whose phase is determined by a classical algorithm prior to running the circuit on a quantum device. Such circuits are used in variational a…

Jerzy Paczos, Joshua Foo, and Magdalena Zych,

Quantum 9, 1827 (2025).

We propose an experimental setup to probe the interplay between the quantum superposition principle and gravitational time dilation arising from the mass-energy equivalence. It capitalizes o…

Matthew Steinberg, Junyu Fan, Robert J. Harris, David Elkouss, Sebastian Feld, and Alexander Jahn,

Quantum 9, 1826 (2025).

We introduce a new class of qubit codes that we call Evenbly codes, building on a previous proposal of hyperinvariant tensor networks. Its tensor network description consists of local, non-p…

Jan Nöller, Nikolai Miklin, Martin Kliesch, and Mariami Gachechiladze,

Quantum 9, 1825 (2025).

The rapid advancement of quantum hardware necessitates the development of reliable methods to certify its correct functioning. However, existing certification tests fall short, as they eithe…

Piotr T. Grochowski, Hannes Pichler, Cindy A. Regal, and Oriol Romero-Isart,

Quantum 9, 1824 (2025).

We present a theoretical proposal for preparing and manipulating a state of a single continuous-variable degree of freedom confined to a nonharmonic potential. By utilizing optimally control…

Hiroyuki Harada, Yasunari Suzuki, Bo Yang, Yuuki Tokunaga, and Suguru Endo,

Quantum 9, 1823 (2025).

The hybrid tensor network (HTN) method is a general framework allowing for the construction of an effective wavefunction with the combination of classical tensors and quantum tensors, i.e.,…

Phattharaporn Singkanipa, Zihan Xia, and Daniel A. Lidar,

Quantum 9, 1821 (2025).

In the absence of fault tolerant quantum error correction for analog, Hamiltonian quantum computation, error suppression via energy penalties is an effective alternative. We construct famili…

Michael J. Kastoryano, Lasse B. Kristensen, Chi-Fang Chen, and Andras Gilyén,

Quantum 9, 1820 (2025).

We investigate the emergence of stable subspaces in the low-temperature quantum thermal dynamics of finite spin chains. Our analysis reveals the existence of effective decoherence-free qudit…

Laurens Walleghem, Yìlè Yīng, Rafael Wagner, and David Schmid,

Quantum 9, 1819 (2025).

The Local Friendliness argument is an extended Wigner's friend no-go theorem that provides strong constraints on the nature of reality – stronger even than those imposed by Bell's theorem or…

Lauritz van Luijk, Alexander Stottmeister, and Henrik Wilming,

Quantum 9, 1818 (2025).

Embezzlement of entanglement refers to the task of extracting entanglement from an entanglement resource via local operations and without communication while perturbing the resource arbitrar…

Ahmed A. Akhtar, Namit Anand, Jeffrey Marshall, and Yi-Zhuang You,

Quantum 9, 1816 (2025).

We introduce “dual-unitary shadow tomography'' (DUST), a classical shadow tomography protocol based on dual-unitary brick-wall circuits. To quantify the performance of DUST, we study operato…

Daniel Collins and Sandu Popescu,

Quantum 9, 1815 (2025).

In the paradigmatic example of quantum measurements, whenever one measures a system which starts in a superposition of two states of a conserved quantity, it jumps to one of the two states,…

Tommaso Grigoletto, Yukuan Tao, Francesco Ticozzi, and Lorenza Viola,

Quantum 9, 1814 (2025).

We consider finite-dimensional many-body quantum systems described by time-independent Hamiltonians and Markovian master equations, and present a systematic method for constructing smaller-d…

Preetham Mohan and Ambuj Tewari,

Quantum 9, 1813 (2025).

Arunachalam and de Wolf (2018) [1] showed that the sample complexity of quantum batch learning of boolean functions, in the realizable and agnostic settings, has the…

Stefano Mangini and Daniel Cavalcanti,

Quantum 9, 1812 (2025).

Accurately estimating the properties of quantum systems is a central challenge in quantum computing and quantum information. We propose a method to obtain unbiased estimators of multiple obs…

Kees van Berkel, Jan de Graaf, and Kees van Hee,

Quantum 9, 1811 (2025).

We derive a class of cellular automata for the Schrödinger Hamiltonian, including scalar and vector potentials. It is based on a multi-split of the Hamiltonian, resulting in a multi-step uni…

Long D. H. My, Shushen Qin, and Hui Khoon Ng,

Quantum 9, 1810 (2025).

Bosonic codes encode quantum information into a single infinite-dimensional physical system endowed with error correction capabilities. This reduces the need for complex management of many p…

Lina Vandré, Boxuan Jing, Yu Xiang, Otfried Gühne, and Qiongyi He,

Quantum 9, 1809 (2025).

We provide a graphical method to describe and analyze non-Gaussian quantum states using a hypergraph framework. These states are pivotal resources for quantum computing, communication, and m…

Dimitris Saraidaris and Alexander Jahn,

Quantum 9, 1808 (2025).

Discrete models of holographic dualities, typically modeled by tensor networks on hyperbolic tilings, produce quantum states with a characteristic quasiperiodic disorder not present in conti…

Luca Gravina, Vincenzo Savona, and Filippo Vicentini,

Quantum 9, 1803 (2025).

We investigate the challenge of classical simulation of unitary quantum dynamics with variational Monte Carlo approaches, addressing the instabilities and high computational demands of exist…

Edoardo Ballini, Julius Mildenberger, Matteo M. Wauters, and Philipp Hauke,

Quantum 9, 1802 (2025).

Non-Abelian gauge theories underlie our understanding of fundamental forces of modern physics. Simulating them on quantum hardware is an outstanding challenge in the rapidly evolving field o…

Tobias Haug, Leandro Aolita, and M.S. Kim,

Quantum 9, 1801 (2025).

Nonstabilizerness or `magic' is a key resource for quantum computing and a necessary condition for quantum advantage. Non-Clifford operations turn stabilizer states into resourceful states,…

Hyakka Nakada, Kotaro Tanahashi, and Shu Tanaka,

Quantum 9, 1799 (2025).

Quantum computers are expected to enable fast solving of large-scale combinatorial optimization problems. However, their limitations in fidelity and the number of qubits prevent them from ha…

Mourad Halla,

Quantum 9, 1798 (2025).

The Quantum Fisher Information Matrix (QFIM) plays a crucial role in quantum optimization algorithms such as Variational Quantum Imaginary Time Evolution and Quantum Natural Gradient Descent…

Daniele Iannotti, Gianluca Esposito, Lorenzo Campos Venuti, and Alioscia Hamma,

Quantum 9, 1797 (2025).

The interplay between non-stabilizerness and entanglement in random states is a very rich arena of study for the understanding of quantum advantage and complexity. In this work, we tackle th…

Matthias C. Löbl, Love A. Pettersson, Stefano Paesani, and Anders S. Sørensen,

Quantum 9, 1795 (2025).

Graph states are key resources for measurement-based quantum computing, which is particularly promising for photonic systems. Fusions are probabilistic Bell state measurements, measuring pai…

Arthur Braida, Shantanav Chakraborty, Alapan Chaudhuri, Joseph Cunningham, Rutvij Menavlikar, Leonardo Novo, and Jérémie Roland,

Quantum 9, 1790 (2025).

In the circuit model of quantum computing, amplitude amplification techniques can be used to find solutions to NP-hard problems defined on $n$-bits in time $\text{poly}(n) 2^{n/2}$. In this work…

Joe Gibbs and Lukasz Cincio,

Quantum 9, 1789 (2025).

Dynamic quantum simulation is a leading application for achieving quantum advantage. However, high circuit depths remain a limiting factor on near-term quantum hardware. We present a compila…

Oliver O’Brien and Christoph Sünderhauf,

Quantum 9, 1786 (2025).

Efficient state preparation is essential for implementing efficient quantum algorithms. Whilst several techniques for low-cost state preparation exist, this work facilitates further classes…

Gaurang Agrawal, Pritam Halder, and Aditi SenDe,

Quantum 9, 1785 (2025).

We explore the performance of the metrology scheme by employing a quantum time flip during encoding, a specific case of processes with indefinite time direction, which we refer to as indefin…

Júlia Barberà-Rodríguez, Mariana Navarro, and Leonardo Zambrano,

Quantum 9, 1784 (2025).

Direct fidelity estimation is a protocol that estimates the fidelity between an experimental quantum state and a target pure state. By measuring the expectation values of Pauli operators sel…

Yu-Qin Chen, Shuo Liu, and Shi-Xin Zhang,

Quantum 9, 1783 (2025).

In this study, we explore the information capacity of open quantum systems, focusing on the effective channels formed by the subsystem of random quantum circuits and quantum Hamiltonian evol…

Jiace Sun, Lixue Cheng, and Shi-Xin Zhang,

Quantum 9, 1782 (2025).

Stabilizer states, which are also known as the Clifford states, have been commonly utilized in quantum information, quantum error correction, and quantum circuit simulation due to their simp…

Jiawei Wu, Yanglin Hu, Akshay Bansal, and Marco Tomamichel,

Quantum 9, 1780 (2025).

Weak coin flipping is a cryptographic primitive in which two mutually distrustful parties generate a shared random bit to agree on a winner via remote communication. While a stand-alone secu…

Irakli Giorgadze, Haixuan Huang, Jordan Gaines, Elio J. König, and Jukka I. Väyrynen,

Quantum 9, 1778 (2025).

Fermionic Hamiltonians play a critical role in quantum chemistry, one of the most promising use cases for near-term quantum computers. However, since encoding nonlocal fermionic statistics u…

Zane M. Rossi, Jack L. Ceroni, and Isaac L. Chuang,

Quantum 9, 1776 (2025).

Despite significant advances in quantum algorithms, quantum programs in practice are often expressed at the circuit level, forgoing helpful structural abstractions common to their classical…

Zohar Schwartzman-Nowik and Benjamin J. Brown,

Quantum 9, 1775 (2025).

Different choices of quantum error-correcting codes can reduce the demands on the physical hardware needed to build a quantum computer. To achieve the full potential of a code, we must devel…

Zakari Denis and Giuseppe Carleo,

Quantum 9, 1772 (2025).

In recent years, neural quantum states have emerged as a powerful variational approach, achieving state-of-the-art accuracy when representing the ground-state wave function of a great variet…

Zhi Li and Zhu-Xi Luo,

Quantum 9, 1771 (2025).

Symmetry is a powerful tool for understanding phases of matter in equilibrium. Quantum circuits with measurements have recently emerged as a platform for novel states of matter intrinsically…

Lennart Bittel, Francesco Anna Mele, Antonio Anna Mele, Salvatore Tirone, and Ludovico Lami,

Quantum 9, 1769 (2025).

Gaussian states of bosonic quantum systems enjoy numerous technological applications and are ubiquitous in nature. Their significance lies in their simplicity, which in turn rests on the fac…

Áron Márton and János K. Asbóth,

Quantum 9, 1767 (2025).

Logical qubits can be protected against environmental noise by encoding them into a highly entangled state of many physical qubits and actively intervening in the dynamics with stabilizer me…

Santanu Bosu Antu and Sisi Zhou,

Quantum 9, 1766 (2025).

Estimating many-body Hamiltonians has wide applications in quantum technology. By allowing coherent evolution of quantum systems and entanglement across multiple probes, the precision of est…

Tyler Kharazi, Ahmad M. Alkadri, Jin-Peng Liu, Kranthi K. Mandadapu, and K. Birgitta Whaley,

Quantum 9, 1764 (2025).

Simulation of physical systems is one of the most promising use cases of future digital quantum computers. In this work we systematically analyze the quantum circuit complexities of block en…

Ashot Avanesov, Alexander Shurinov, Ivan Dyakonov, and Stanislav Straupe,

Quantum 9, 1762 (2025).

We adopt a method of the quantum gate teleportation for converting circuit-based quantum computation primitives into fusion networks. By using the presented scheme for the CNOT gate we const…

Pengpeng Xiao, Muqing Zheng, Anran Jiao, Xiu Yang, and Lu Lu,

Quantum 9, 1761 (2025).

In the realm of computational science and engineering, constructing models that reflect real-world phenomena requires solving partial differential equations (PDEs) with different conditions.…

Massimiliano Smania, Matthias Kleinmann, Adán Cabello, and Mohamed Bourennane,

Quantum 9, 1760 (2025).

Bell tests have become a powerful tool for quantifying security, randomness, entanglement, and many other properties, as well as for investigating fundamental physical limits. In all these c…

Tobias Haug, Kishor Bharti, and Dax Enshan Koh,

Quantum 9, 1759 (2025).

Pseudorandom quantum states (PRSs) and pseudorandom unitaries (PRUs) possess the dual nature of being efficiently constructible while appearing completely random to any efficient quantum alg…

Jordi Riu, Jan Nogué, Gerard Vilaplana, Artur Garcia-Saez, and Marta P. Estarellas,

Quantum 9, 1758 (2025).

We propose a novel Reinforcement Learning (RL) method for optimizing quantum circuits using graph-theoretic simplification rules of ZX-diagrams. The agent, trained using the Proximal Policy…

Hidetaka Manabe and Yuichi Sano,

Quantum 9, 1755 (2025).

The quantum state preparation of probability distributions is an important subroutine for many quantum algorithms. When embedding $D$-dimensional multivariate probability distributions by disc…

Siddharth Tiwary, Harsh Sharma, and Himadri Shekhar Dhar,

Quantum 9, 1754 (2025).

The transfer and storage of quantum information in a hybrid quantum system, consisting of an ensemble of atoms or spins interacting with a cavity, is adversely affected by the inhomogeneity…

Nikola Paunkovic and Marko Vojinovic,

Quantum 9, 1753 (2025).

We argue that there exists an operational way to establish the observability of the notions of space and time. Specifically, we propose a theory-independent protocol for a gedanken-experimen…

Markku Hahto, Johannes Nokkala, Guillermo García-Pérez, Sabrina Maniscalco, and Jyrki Piilo,

Quantum 9, 1751 (2025).

The goal in quantum state transfer is to avoid the need to physically transport carriers of quantum information. This is achieved by using a suitably engineered Hamiltonian that induces the…

Satoshi Yoshida, Akihito Soeda, and Mio Murao,

Quantum 9, 1750 (2025).

Identification of possible transformations of quantum objects including quantum states and quantum operations is indispensable in developing quantum algorithms. Universal transformations, de…

T. T. Sergeev, E. S. Andrianov, and A. A. Zyablovsky,

Quantum 9, 1746 (2025).

Spontaneous symmetry breaking in systems with symmetry is a cornerstone phenomenon accompanying second-order phase transitions. Here, we predict the opposite phenomenon, namely, spontaneous…

Léo Monbroussou, Eliott Z. Mamon, Jonas Landman, Alex B. Grilo, Romain Kukla, and Elham Kashefi,

Quantum 9, 1745 (2025).

Quantum machine learning (QML) has become a promising area for real world applications of quantum computers, but near-term methods and their scalability are still important research topics.…

Kenneth Goodenough, Tim Coopmans, and Don Towsley,

Quantum 9, 1744 (2025).

Losses are one of the main bottlenecks for the distribution of entanglement in quantum networks, which can be overcome by the implementation of quantum repeaters. The most basic form of a qu…

Rocco Duvenhage, Kyle Oerder, and Keagan van den Heuvel,

Quantum 9, 1743 (2025).

Quantum detailed balance is formulated in terms of elementary transitions, in close analogy to detailed balance in a classical Markov chain on a finite set of points. An elementary transitio…

Sascha Wald, Louie Hong Yao, Thierry Platini, Chris Hooley, and Federico Carollo,

Quantum 9, 1742 (2025).

Time evolution in several classes of quantum devices is generated through the application of quantum gates. Resetting is a critical technological feature in these systems allowing for mid-ci…

David T. Stephen,

Quantum 9, 1738 (2025).

We describe a class of spin chains with new physical and computational properties. On the physical side, the spin chains give examples of symmetry-protected topological phases that are defin…

Francisca Vasconcelos, Emmanouil-Vasileios Vlatakis-Gkaragkounis, Panayotis Mertikopoulos, Georgios Piliouras, and Michael I. Jordan,

Quantum 9, 1737 (2025).

Recent developments in domains such as non-local games, quantum interactive proofs, and quantum generative adversarial networks have renewed interest in quantum game theory and, specifically…

Zhen-Peng Xu, Julio I. de Vicente, Liang-Liang Sun, and Sixia Yu,

Quantum 9, 1736 (2025).

Quantum networks are of high interest nowadays and a quantum internet has been long envisioned. Network-entanglement adapts the notion of entanglement to the network scenario and network-ent…

Mirjam Weilenmann, Costantino Budroni, and Miguel Navascues,

Quantum 9, 1735 (2025).

We study what can or cannot be certified in communication scenarios where the assumption of independence and identical distribution (iid) between experimental rounds fails. In this respect,…

Ma-Cheng Yang and Cong-Feng Qiao,

Quantum 9, 1734 (2025).

We propose in this work a practical approach to address the longstanding and challenging problem of quantum separability, leveraging the correlation matrices of generic observables. General…

Tim Weaving, Alexis Ralli, Peter J. Love, Sauro Succi, and Peter V. Coveney,

Quantum 9, 1732 (2025).

We present an error mitigation strategy composed of Echo Verification (EV) and Clifford Data Regression (CDR), the combination of which allows one to learn the effect of the quantum noise ch…

Mykolas Sveistrys, Josias Langbehn, Raphaël Menu, Steve Campbell, Giovanna Morigi, and Christiane P. Koch,

Quantum 9, 1731 (2025).

Building on the insight that engineered noise, specifically, engineered dephasing can enhance the adiabaticity of controlled quantum dynamics, we investigate how a dephasing-generating coupl…

Guillermo González-García, J. Ignacio Cirac, and Rahul Trivedi,

Quantum 9, 1730 (2025).

For random quantum circuits on $n$ qubits of depth $\Theta(\log n)$ with depolarizing noise, the task of sampling from the output state can be efficiently performed classically using a Pauli pat…

Niklas Hörnedal, Oskar A. Prośniak, Adolfo del Campo, and Aurélia Chenu,

Quantum 9, 1729 (2025).

Non-Hermitian dynamics in quantum systems preserves the rank of the state density operator. Using this insight, we develop a geometric framework to describe its time evolution. In particular…

Christopher A. Pattison, Anirudh Krishna, and John Preskill,

Quantum 9, 1728 (2025).

Constant-rate low-density parity-check (LDPC) codes are promising candidates for constructing efficient fault-tolerant quantum memories. However, if physical gates are subject to geometric-l…

Piotr Czarnik, Michael McKerns, Andrew T. Sornborger, and Lukasz Cincio,

Quantum 9, 1727 (2025).

Error mitigation will play an important role in practical applications of near-term noisy quantum computers. Current error mitigation methods typically concentrate on correction quality at t…

Tom O’Leary, Lewis W. Anderson, Dieter Jaksch, and Martin Kiffner,

Quantum 9, 1726 (2025).

We present an iterative generalisation of the quantum subspace expansion algorithm used with a Krylov basis. The iterative construction connects a sequence of subspaces via their lowest ener…

Hongye Yu and Tzu-Chieh Wei,

Quantum 9, 1724 (2025).

Current noisy quantum computers have multiple types of errors, which can occur in the state preparation, measurement/readout, and gate operation, as well as intrinsic decoherence and relaxat…

Ziang Wang, Feng Wu, Hui-Hai Zhao, Xin Wan, and Xiaotong Ni,

Quantum 9, 1722 (2025).

One significant advantage of superconducting processors is their extensive design flexibility, which encompasses various types of qubits and interactions. Given the large number of tunable p…

Vittorio D’Esposito, Giuseppe Fabiano, Domenico Frattulillo, and Flavio Mercati,

Quantum 9, 1721 (2025).

Motivated by the expectation that relativistic symmetries might acquire quantum features in Quantum Gravity, we take the first steps towards a theory of ''Doubly'' Quantum Mechanics, a modif…

Adam Burchardt and Frederik Hahn,

Quantum 9, 1720 (2025).

This paper introduces the foliage partition, an easy-to-compute LC-invariant for graph states, of computational complexity $\mathcal{O}(n^3)$ in the number of qubits. Inspired by the foliage o…

Szilárd Szalay and Géza Tóth,

Quantum 9, 1718 (2025).

We work out the general theory of one-parameter families of partial entanglement properties and the resulting entanglement depth-like quantities. Special cases of these are the depth of part…

Jordi Weggemans,

Quantum 9, 1717 (2025).

In unitary property testing a quantum algorithm, also known as a tester, is given query access to a black-box unitary and has to decide whether it satisfies some property. We propose a new t…

Yaroslav Balytskyi, Yevgen Kotukh, Gennady Khalimov, and Sang-Yoon Chang,

Quantum 9, 1716 (2025).

$\mathcal{PT}$-symmetric systems have garnered significant attention due to their unconventional properties. Despite the growing interest, there remains an ongoing debate about whether these s…

Dominique Spehner,

Quantum 9, 1715 (2025).

We study the geodesics on the manifold of mixed quantum states for the Bures metric. It is shown that these geodesics correspond to physical non-Markovian evolutions of the system coupled to…

Marco Ballarin, Pietro Silvi, Simone Montangero, and Daniel Jaschke,

Quantum 9, 1714 (2025).

We introduce an optimal strategy to sample quantum outcomes of local measurement strings for isometric tensor network states. Our method generates samples based on an exact cumulative boundi…

Simone Roncallo, Xi Lu, and Lorenzo Maccone,

Quantum 9, 1713 (2025).

We propose an interferometric scheme where each photon returns one bit of the binary expansion of an unknown phase. It sets up a method for estimating the phase value at arbitrary uncertaint…

Llorenç Escolà-Farràs and Florian Speelman,

Quantum 9, 1712 (2025).

Extended non-local games are a generalization of monogamy-of-entanglement games, played by two quantum parties and a quantum referee that performs a measurement on their local quantum system…

Niv Bharos, Liubov Markovich, and Johannes Borregaard,

Quantum 9, 1711 (2025).

The use of higher-dimensional photonic encodings (qudits) instead of two-dimensional encodings (qubits) can improve the loss tolerance and reduce the computational resources of photonic-base…

Matias Bundgaard-Nielsen, Dirk Englund, Mikkel Heuck, and Stefan Krastanov,

Quantum 9, 1710 (2025).

In this paper, we introduce a numerical framework designed to solve problems within the emerging field of Waveguide Quantum Electrodynamics (WQED). The framework is based on collision quantu…

Felix Fritzsch, Maximilian F. I. Kieler, and Arnd Bäcker,

Quantum 9, 1709 (2025).

While the notion of quantum chaos is tied to random matrix spectral correlations, also eigenstate properties in chaotic systems are often assumed to be described by random matrix theory. Ana…

Zoltán Kolarovszki, Tomasz Rybotycki, Péter Rakyta, Ágoston Kaposi, Boldizsár Poór, Szabolcs Jóczik, Dániel T. R. Nagy, Henrik Varga, Kareem H. El-Safty, Gregory Morse, Michał Oszmaniec, Tamás Kozsik, and Zoltán Zimborás,

Quantum 9, 1708 (2025).

We introduce the Piquasso quantum programming framework, a full-stack open-source software platform for the simulation and programming of photonic quantum computers. Piquasso can be programm…

Varun Narasimhachar,

Quantum 9, 1707 (2025).

Quantum coherence—an indispensable resource for quantum technologies—is known to be distillable from a noisy form using operations that cannot create it. However, distillation exacts a hidde…

Llorenç Escolà-Farràs, Jaròn Has, Maris Ozols, Christian Schaffner, and Mehrdad Tahmasbi,

Quantum 9, 1706 (2025).

Local simultaneous state discrimination (LSSD) is a recently introduced problem in quantum information processing. Its classical version is a non-local game played by non-communicating playe…

Mykola Semenyakin, Yevheniia Cheipesh, and Yaroslav Herasymenko,

Quantum 9, 1705 (2025).

Understanding the structure of quantum correlations in a many-body system is key to its computational treatment. For fermionic systems, correlations can be defined as deviations from Slater…

Aaron Szasz, Ed Younis, and Wibe Albert de Jong,

Quantum 9, 1704 (2025).

Models of interacting many-body quantum systems that may realize new exotic phases of matter, notably quantum spin liquids, are challenging to study using even state-of-the-art classical met…

Matthias Rosenkranz, Eric Brunner, Gabriel Marin-Sanchez, Nathan Fitzpatrick, Silas Dilkes, Yao Tang, Yuta Kikuchi, and Marcello Benedetti,

Quantum 9, 1703 (2025).

A fundamental step of any quantum algorithm is the preparation of qubit registers in a suitable initial state. Often qubit registers represent a discretization of continuous variables and th…

Jorge Miguel-Ramiro, Alexander Pirker, and Wolfgang Dür,

Quantum 9, 1702 (2025).

Entanglement purification and distillation protocols are essential for harnessing the full potential of quantum communication technologies. Multiple strategies have been proposed to approach…

F. Setiawan, Alexander V. Gramolin, Elisha S. Matekole, Hari Krovi, and Jacob M. Taylor,

Quantum 9, 1701 (2025).

Accurate modeling of noise in realistic quantum processors is critical for constructing fault-tolerant quantum computers. While a full simulation of actual noisy quantum circuits provides in…

Klára Baksová, Olga Leskovjanová, Ladislav Mišta Jr., Elizabeth Agudelo, and Nicolai Friis,

Quantum 9, 1699 (2025).

Multi-copy activation of genuine multipartite entanglement (GME) is a phenomenon whereby multiple copies of biseparable but fully inseparable states can exhibit GME. This was shown to be gen…

Ritu Nehra, Alessandro Romito, and Dganit Meidan,

Quantum 9, 1697 (2025).

We study the evolution of a quantum many-body system driven by two competing measurements, which induces a topological entanglement transition between two distinct area law phases. We employ…

Gregory A. L. White, Felix A. Pollock, Lloyd C. L. Hollenberg, Charles D. Hill, and Kavan Modi,

Quantum 9, 1695 (2025).

Multi-time quantum processes are endowed with the same richness as multipartite states, including temporal entanglement and exotic causal structures. However, experimentally probing these ri…

Siyi Yang and Robert Calderbank,

Quantum 9, 1693 (2025).

Spatially-coupled (SC) codes is a class of convolutional LDPC codes that has been well investigated in classical coding theory thanks to their high performance and compatibility with low-lat…

Xiaozhou Feng, Nadezhda Fishchenko, Sarang Gopalakrishnan, and Matteo Ippoliti,

Quantum 9, 1692 (2025).

The dynamics of monitored systems can exhibit a measurement-induced phase transition (MIPT) between entangling and disentangling phases, tuned by the measurement rate. When the dynamics obey…

Jean-Gabriel Hartmann, Denis Janković, Rémi Pasquier, Mario Ruben, and Paul-Antoine Hervieux,

Quantum 9, 1690 (2025).

High-dimensional quantum computing has generated significant interest due to its potential to address scalability and error correction challenges faced by traditional qubit-based systems. Th…

Hugo Delavenne, François Le Gall, Yupan Liu, and Masayuki Miyamoto,

Quantum 9, 1688 (2025).

Complexity theory typically focuses on the difficulty of solving computational problems using classical inputs and outputs, even with a quantum computer. In the quantum world, it is natural…

Santiago Llorens, Walther González, Gael Sentís, John Calsamiglia, Ramon Muñoz-Tapia, and Emili Bagan,

Quantum 9, 1687 (2025).

This paper introduces quantum edge detection, aimed at locating boundaries of quantum domains where all particles share the same pure state. Focusing on the 1D scenario of a string of partic…

Vikram Ravindranath, Zhi-Cheng Yang, and Xiao Chen,

Quantum 9, 1685 (2025).

We study free fermion systems under adaptive quantum dynamics consisting of unitary gates and projective measurements followed by corrective unitary operations. We further introduce a classi…

Sourav Biswas, E. Rico, and Tobias Grass,

Quantum 9, 1683 (2025).

In the presence of ring exchange interactions, bosons in a ladder-like lattice may form the bosonic analogon of a correlated metal, known as the d-wave Bose liquid (DBL). In this paper, we s…

Oriel Kiss, Utkarsh Azad, Borja Requena, Alessandro Roggero, David Wakeham, and Juan Miguel Arrazola,

Quantum 9, 1682 (2025).

We investigate the feasibility of early fault-tolerant quantum algorithms focusing on ground-state energy estimation problems. In particular, we examine the computation of the cumulative dis…

Titouan Carette, Jan Glowacki, and Leon Loveridge,

Quantum 9, 1680 (2025).

Quantum reference frames are needed in quantum theory for much the same reasons that reference frames are in classical theories: to manifest invariance in line with fundamental relativity pr…

Alessandro Foligno and Bruno Bertini,

Quantum 9, 1678 (2025).

The growth of the entanglement between two disjoint intervals and its complement after a quantum quench is regarded as a dynamical chaos indicator. Namely, it is expected to show qualitative…

Stefano Longhi,

Quantum 9, 1677 (2025).

The behavior of systems far from equilibrium is often complex and unpredictable, challenging and sometimes overturning the physical intuition derived from equilibrium scenarios. One striking…

Jintae Kim, Jung Hoon Han, and Isaac H. Kim,

Quantum 9, 1676 (2025).

We propose a fault-tolerant quantum error correction architecture consisting of a linear array of emitters and delay lines. In our scheme, a resource state for fault-tolerant quantum computa…

Hannah Lange, Guillaume Bornet, Gabriel Emperauger, Cheng Chen, Thierry Lahaye, Stefan Kienle, Antoine Browaeys, and Annabelle Bohrdt,

Quantum 9, 1675 (2025).

Owing to their great expressivity and versatility, neural networks have gained attention for simulating large two-dimensional quantum many-body systems. However, their expressivity comes wit…

Joao F. Doriguello, Debbie Lim, Chi Seng Pun, Patrick Rebentrost, and Tushar Vaidya,

Quantum 9, 1674 (2025).

We present a novel quantum high-dimensional linear regression algorithm with an $\ell_1$-penalty based on the classical LARS (Least Angle Regression) pathwise algorithm. Similarly to available…

Andreas Bauer,

Quantum 9, 1673 (2025).

We propose a family of explicit geometrically local circuits on a 2-dimensional planar grid of qudits, realizing any abelian non-chiral topological phase as an actively error-corrected fault…

Simon Buchholz, Jonas M. Kübler, and Bernhard Schölkopf,

Quantum 9, 1672 (2025).

Multi-armed bandits are one of the theoretical pillars of reinforcement learning. Recently, the investigation of quantum algorithms for multi-armed bandit problems was started, and it was fo…

Enrico Di Benedetto, Alejandro Gonzalez-Tudela, and Francesco Ciccarello,

Quantum 9, 1671 (2025).

Flat bands (FBs) are energy bands with zero group velocity, which in electronic systems were shown to favor strongly correlated phenomena. Indeed, a FB can be spanned with a basis of strictl…

Jordan K. Taylor and Ian P. McCulloch,

Quantum 9, 1670 (2025).

We propose a definition of wavefunction "branchings": quantum superpositions which can't be feasibly distinguished from the corresponding mixed state, even under time evolution. Our definiti…

Lewis W. Anderson, Martin Kiffner, Tom O’Leary, Jason Crain, and Dieter Jaksch,

Quantum 9, 1669 (2025).

Computing vacuum states of lattice gauge theories (LGTs) containing fermionic degrees of freedom can present significant challenges for classical computation using Monte-Carlo methods. Quant…

Faidon Andreadakis and Paolo Zanardi,

Quantum 9, 1668 (2025).

In quantum many-body systems, complex dynamics delocalize the physical degrees of freedom. This spreading of information throughout the system has been extensively studied in relation to qua…

Geshuo Wang, Siyao Yang, and Zhenning Cai,

Quantum 9, 1667 (2025).

We propose an algorithm that combines the inchworm method and the frozen Gaussian approximation to simulate the Caldeira-Leggett model in which a quantum particle is coupled with thermal har…

Lennart Bittel, Antonio A. Mele, Jens Eisert, and Lorenzo Leone,

Quantum 9, 1665 (2025).

Free-fermionic states, also known as matchgates or Gaussian states, are a fundamental class of quantum states due to their efficient classical simulability and their crucial role across vari…

Bence Bakó, Adam Glos, Özlem Salehi, and Zoltán Zimborás,

Quantum 9, 1663 (2025).

Current state-of-the-art quantum optimization algorithms require representing the original problem as a binary optimization problem, which is then converted into an equivalent cost Hamiltoni…

Colin Read, Eduardo Serrano-Ensástiga, and John Martin,

Quantum 9, 1661 (2025).

In the NISQ era, where quantum information processing is hindered by the decoherence and dissipation of elementary quantum systems, developing new protocols to extend the lifetime of quantum…

Shaojun Wu, Shan Jin, Dingding Wen, Donghong Han, and Xiaoting Wang,

Quantum 9, 1660 (2025).

Quantum reinforcement learning (QRL) is a promising paradigm for near-term quantum devices. While existing QRL methods have shown success in discrete action spaces, extending these technique…

Evandro C. R. Rosa, Eduardo I. Duzzioni, and Rafael de Santiago,

Quantum 9, 1659 (2025).

This paper presents novel methods for optimizing multi-controlled quantum gates, which naturally arise in high-level quantum programming. Our primary approach involves rewriting $U(2)$ gates a…

Alberto Manzano, David Dechant, Jordi Tura, and Vedran Dunjko,

Quantum 9, 1658 (2025).

Parametrized quantum circuits (PQC) are quantum circuits which consist of both fixed and parametrized gates. In recent approaches to quantum machine learning (QML), PQCs are essentially ubiq…

Andrés González Lorente, Pablo V. Parellada, Miguel Castillo-Celeita, and Mateus Araújo,

Quantum 9, 1657 (2025).

Computing key rates in quantum key distribution (QKD) numerically is essential to unlock more powerful protocols, that use more sophisticated measurement bases or quantum systems of higher d…

Stefano Marcantoni and Marco Merkli,

Quantum 9, 1656 (2025).

We study the dynamics of an open quantum system linearly coupled to a bosonic reservoir. We show that, in the ultrastrong coupling limit, the system undergoes a nonselective measurement and…

Enrique Cervero-Martí­n and Marco Tomamichel,

Quantum 9, 1652 (2025).

We analyse two party non-local games whose predicate requires Alice and Bob to generate matching bits, and their three party extensions where a third player receives all inputs and is requir…

Tara Kalsi, Alessandro Romito, and Henning Schomerus,

Quantum 9, 1651 (2025).

A key conjecture about the evolution of complex quantum systems towards an ergodic steady state, known as scrambling, is that this process acquires universal features when it is most efficie…

Mankei Tsang,

Quantum 9, 1650 (2025).

The fascinating concept of coherent quantum absorber – which can absorb any photon emitted by another system while maintaining entanglement with that system – has found diverse implications…

Andreas Klingler, Tim Netzer, and Gemma De les Coves,

Quantum 9, 1649 (2025).

The matrix rank and its positive versions are robust for small approximations, i.e. they do not decrease under small perturbations. In contrast, the multipartite tensor rank can collapse for…

Rajeev Gangwar, Tanmoy Pandit, Kaumudibikash Goswami, Siddhartha Das, and Manabendra Nath Bera,

Quantum 9, 1646 (2025).

Quantum non-Markovianity in tripartite quantum states $\rho_{ABC}$ represents a correlation between systems $A$ and $C$ when conditioned on the system $B$ and is known to have both classical and qua…

Georgios Styliaris, Rahul Trivedi, David Perez-Garcia, and J. Ignacio Cirac,

Quantum 9, 1645 (2025).

Matrix-product unitaries (MPU) are 1D tensor networks describing time evolution and unitary symmetries of quantum systems, while their action on states by construction preserves the entangle…

Tommaso Guaita,

Quantum 9, 1644 (2025).

Known mappings that encode fermionic modes into a bosonic qubit system are non-local transformations. In this paper we establish that this must necessarily be the case, if the locality graph…

Cica Gustiani, Tyson Jones, and Simon C. Benjamin,

Quantum 9, 1642 (2025).

We present the Virtual Quantum Device (VQD) platform, a system based on the QuEST quantum emulator. Through the use of VQDs, non-expert users can emulate specific quantum computers with deta…

Lorenzo Laneve and Stefan Wolf,

Quantum 9, 1641 (2025).

Quantum signal processing (QSP) is a framework which was proven to unify and simplify a large number of known quantum algorithms, as well as discovering new ones. QSP allows one to transform…

Ryan Sweke, Erik Recio-Armengol, Sofiene Jerbi, Elies Gil-Fuster, Bryce Fuller, Jens Eisert, and Johannes Jakob Meyer,

Quantum 9, 1640 (2025).

Quantum machine learning is arguably one of the most explored applications of near-term quantum devices. Much focus has been put on notions of variational quantum machine learning where {par…

Reinis Irmejs and Raul A. Santos,

Quantum 9, 1639 (2025).

One of the most important quantities characterizing the microscopic properties of quantum systems are dynamical correlation functions. These correlations are obtained by time-evolving a pert…

Yahui Chai, Arianna Crippa, Karl Jansen, Stefan Kühn, Vincent R. Pascuzzi, Francesco Tacchino, and Ivano Tavernelli,

Quantum 9, 1638 (2025).

Quantum computing provides a novel avenue towards simulating dynamical phenomena, and, in particular, scattering processes relevant for exploring the structure of matter. However, preparing…

Niels Kornerup, Jonathan Sadun, and David Soloveichik,

Quantum 9, 1636 (2025).

Pebble games are popular models for analyzing time-space trade-offs. In particular, reversible pebble game strategies are frequently applied in quantum algorithms like Grover's search to eff…

Lucas Marti, Refik Mansuroglu, and Michael J. Hartmann,

Quantum 9, 1635 (2025).

We present a cooling algorithm for ground state preparation of fermionic Hamiltonians. Our algorithm makes use of the Hamiltonian simulation of the considered system coupled to an ancillary…

Lukas Schmitt, Christophe Piveteau, and David Sutter,

Quantum 9, 1634 (2025).

Quasiprobabilistic cutting techniques allow us to partition large quantum circuits into smaller subcircuits by replacing non-local gates with probabilistic mixtures of local gates. The cost…

Qiang Miao and Thomas Barthel,

Quantum 9, 1631 (2025).

Strongly-correlated quantum many-body systems are difficult to study and simulate classically. We recently proposed a variational quantum eigensolver (VQE) based on the multiscale entangleme…

Joshua Foo and Magdalena Zych,

Quantum 9, 1629 (2025).

Recent results in relativistic quantum information and quantum thermodynamics have independently shown that in the quantum regime, a system may fail to thermalise when subject to quantum-con…

Fabio Costa, Jonathan Barrett, and Sally Shrapnel,

Quantum 9, 1628 (2025).

What does it mean for a causal structure to be `unknown'? Can we even talk about `repetitions' of an experiment without prior knowledge of causal relations? And under what conditions can we…

Ryotaro Suzuki, Jonas Haferkamp, Jens Eisert, and Philippe Faist,

Quantum 9, 1627 (2025).

Recently, the dynamics of quantum systems that involve both unitary evolution and quantum measurements have attracted attention due to the exotic phenomenon of measurement-induced phase tran…

Erez Abrams, Michael Kasprzak, Gaurav Bhole, Tak-San Ho, and Herschel Rabitz,

Quantum 9, 1626 (2025).

Hamiltonian encoding is a methodology for revealing the mechanism behind the dynamics governing controlled quantum systems. In this paper, following Mitra and Rabitz [9], we define mechanism…

Juan Zurita, Andrés Agustí Casado, Charles E. Creffield, and Gloria Platero,

Quantum 9, 1625 (2025).

In the ongoing effort towards a scalable quantum computer, multiple technologies have been proposed. Some of them exploit topological materials to process quantum information. In this work,…

Erenay Karacan, Yanbin Chen, and Christian B. Mendl,

Quantum 9, 1624 (2025).

Hamiltonian simulation is a domain where quantum computers have the potential to outperform their classical counterparts. One of the main challenges of such quantum algorithms is increasing…

César Benito, Esperanza López, Borja Peropadre, and Alejandro Bermudez,

Quantum 9, 1623 (2025).

Topological quantum error correction is a milestone in the scaling roadmap of quantum computers, which targets circuits with trillions of gates that would allow running quantum algorithms fo…

Argyris Giannisis Manes and Jahan Claes,

Quantum 9, 1618 (2025).

Unlike the surface code, quantum low-density parity-check (QLDPC) codes can have a finite encoding rate, potentially lowering the error correction overhead. However, finite-rate QLDPC codes…

Phattharaporn Singkanipa and Daniel A. Lidar,

Quantum 9, 1617 (2025).

Variational quantum algorithms (VQAs) hold much promise but face the challenge of exponentially small gradients. Unmitigated, this barren plateau (BP) phenomenon leads to an exponential trai…

Ladina Hausmann, Alexander Schmidhuber, and Esteban Castro-Ruiz,

Quantum 9, 1616 (2025).

The Page-Wootters formalism is a proposal for reconciling the background-dependent, quantum-mechanical notion of time with the background independence of general relativity. However, the phy…

Tom Holden-Dye, Lluis Masanes, and Arijeet Pal,

Quantum 9, 1615 (2025).

Dual-unitary quantum circuits have recently attracted attention as an analytically tractable model of many-body quantum dynamics. Consisting of a 1+1D lattice of 2-qudit gates arranged in a…

Camille L Latune and Cyril Elouard,

Quantum 9, 1614 (2025).

Considering a general microscopic model for a quantum measuring apparatus comprising a quantum probe coupled to a thermal bath, we analyze the energetic resources necessary for the realizati…

Shin Nishio, Nicholas Connolly, Nicolò Lo Piparo, William John Munro, Thomas Rowan Scruby, and Kae Nemoto,

Quantum 9, 1613 (2025).

Connecting multiple processors via quantum interconnect technologies could help overcome scalability issues in single-processor quantum computers. Transmission via these interconnects can be…

Martin Sandfuchs, Marcus Haberland, V. Vilasini, and Ramona Wolf,

Quantum 9, 1611 (2025).

The design of quantum protocols for secure key generation poses many challenges: On the one hand, they need to be practical concerning experimental realisations. On the other hand, their the…

Andrea Calcinari and Steffen Gielen,

Quantum 9, 1610 (2025).

Group field theory posits that spacetime is emergent and is hence defined without any background notion of space or time; dynamical questions are formulated in relational terms, in particula…

Seok-Hyung Lee, Andrew Li, and Stephen D. Bartlett,

Quantum 9, 1609 (2025).

Two-dimensional color codes are a promising candidate for fault-tolerant quantum computing, as they have high encoding rates, transversal implementation of logical Clifford gates, and resour…

Andreas Bluhm, Leevi Leppäjärvi, and Ion Nechita,

Quantum 9, 1608 (2025).

In the quest for robust and universal quantum devices, the notion of simulation plays a crucial role, both from a theoretical and from an applied perspective. In this work, we go beyond the…

Zhuo Chen, Guoding Liu, and Xiongfeng Ma,

Quantum 9, 1606 (2025).

Quantum learning tasks often leverage randomly sampled quantum circuits to characterize unknown systems. An efficient approach known as “circuit reusing,'' where each circuit is executed mu…

Maria Flors Mor-Ruiz, Julius Wallnöfer, and Wolfgang Dür,

Quantum 9, 1605 (2025).

Entanglement-based quantum networks exhibit a unique flexibility in the choice of entangled resource states that are then locally manipulated by the nodes to fulfill any request in the netwo…

Akshay Bansal and Jamie Sikora,

Quantum 9, 1602 (2025).

In the last two decades, there has been much effort in finding secure protocols for two-party cryptographic tasks. It has since been discovered that even with quantum mechanics, many such pr…

Metod Saniga, Frédéric Holweck, Colm Kelleher, Axel Muller, Alain Giorgetti, and Henri de Boutray,

Quantum 9, 1601 (2025).

Split Cayley hexagons of order two are distinguished finite geometries living in the three-qubit symplectic polar space in two different forms, called classical and skew. Although neither of…

Oscar Higgott and Craig Gidney,

Quantum 9, 1600 (2025).

In this work, we introduce a fast implementation of the minimum-weight perfect matching (MWPM) decoder, the most widely used decoder for several important families of quantum error correctin…

Mayalakshmi Kolangatt, Thigazholi Muruganandan, Sahil Gopalkrishna Naik, Tamal Guha, Manik Banik, and Sutapa Saha,

Quantum 9, 1599 (2025).

Hardy's argument constitutes an elegantly logical test for identifying nonlocal features of multipartite correlations. In this paper, we investigate Hardy's nonlocal behavior within a broad…

Anna Szymusiak and Wojciech Słomczyński,

Quantum 9, 1598 (2025).

In a Generalised Probabilistic Theory (GPT) equipped additionally with some extra geometric structure we define the morphophoric measurements as those for which the measurement map sending s…

Štěpán Šmíd and Roberto Bondesan,

Quantum 9, 1597 (2025).

In this work, we consider a fundamental task in quantum many-body physics – finding and learning ground states of quantum Hamiltonians and their properties. Recent works have studied the tas…

Luís Bugalho, Majid Hassani, Yasser Omar, and Damian Markham,

Quantum 9, 1596 (2025).

Distributed quantum sensing enables the estimation of multiple parameters encoded in spatially separated probes. While traditional quantum sensing is often focused on estimating a single par…

Josep Batle, Tomasz Białecki, Tomasz Rybotycki, Jakub Tworzydło, and Adam Bednorz,

Quantum 9, 1595 (2025).

We improve the test to show the impossibility of a quantum theory based on real numbers by a larger ratio of complex-to-real bound on a Bell-type parameter. In contrast to previous theoretic…

Ruho Kondo, Yuki Sato, Rudy Raymond, and Naoki Yamamoto,

Quantum 9, 1594 (2025).

Quantum optimization methods use a continuous degree-of-freedom of quantum states to heuristically solve combinatorial problems, such as the MAX-CUT problem, which can be attributed to vario…

Nadish de Silva, Wilfred Salmon, and Ming Yin,

Quantum 9, 1586 (2025).

The stabiliser formalism plays a central role in quantum computing, error correction, and fault tolerance. Conversions between and verifications of different specifications of stabiliser sta…

Mohammadsadegh Khazali,

Quantum 9, 1585 (2025).

Optical lattices serve as fundamental building blocks for atomic quantum technology. However, the scale and resolution of these lattices are diffraction-limited to the light wavelength. In c…

Cameron Foreman, Richie Yeung, Alec Edgington, and Florian J. Curchod,

Quantum 9, 1584 (2025).

We present $\texttt{Cryptomite}$, a Python library of randomness extractor implementations. The library offers a range of two-source, seeded and deterministic randomness extractors, together w…

Srijita Kundu and Ernest Y.-Z. Tan,

Quantum 9, 1582 (2025).

Uncloneable encryption, first introduced by Broadbent and Lord (TQC 2020) is a quantum encryption scheme in which a quantum ciphertext cannot be distributed between two non-communicating par…

Nicholas LaRacuente, Kaitlin N. Smith, Poolad Imany, Kevin L. Silverman, and Frederic T. Chong,

Quantum 9, 1581 (2025).

A core challenge for superconducting quantum computers is to scale up the number of qubits in each processor without increasing noise or cross-talk. Distributed quantum computing across smal…