Quantum

Paper

Multipartite Intrinsic Non-Locality and Device-Independent Conference Key Agreement

Aby Philip, Eneet Kaur, Peter Bierhorst, and Mark M. Wilde,

Quantum 7, 898 (2023).

In this work, we introduce multipartite intrinsic non-locality as a method for quantifying resources in the multipartite scenario of device-independent (DI) conference key agreement. We prov…

Paper

Extending the fair sampling assumption using causal diagrams

Valentin Gebhart and Augusto Smerzi,

Quantum 7, 897 (2023).

Discarding undesirable measurement results in Bell experiments opens the detection loophole that prevents a conclusive demonstration of nonlocality. As closing the detection loophole represe…

Paper

Overlapped grouping measurement: A unified framework for measuring quantum states

Bujiao Wu, Jinzhao Sun, Qi Huang, and Xiao Yuan,

Quantum 7, 896 (2023).

Quantum algorithms designed for realistic quantum many-body systems, such as chemistry and materials, usually require a large number of measurements of the Hamiltonian. Exploiting different…

Paper

Random access codes via quantum contextual redundancy

Giancarlo Gatti, Daniel Huerga, Enrique Solano, and Mikel Sanz,

Quantum 7, 895 (2023).

We propose a protocol to encode classical bits in the measurement statistics of many-body Pauli observables, leveraging quantum correlations for a random access code. Measurement contexts bu…

Paper

QKD parameter estimation by two-universal hashing

Dimiter Ostrev,

Quantum 7, 894 (2023).

This paper proposes and proves security of a QKD protocol which uses two-universal hashing instead of random sampling to estimate the number of bit flip and phase flip errors. This protocol…

Paper

Structural risk minimization for quantum linear classifiers

Casper Gyurik, Dyon Vreumingen, van, and Vedran Dunjko,

Quantum 7, 893 (2023).

Quantum machine learning (QML) models based on parameterized quantum circuits are often highlighted as candidates for quantum computing's near-term “killer application''. However, the unders…

Paper

Binary Control Pulse Optimization for Quantum Systems

Xinyu Fei, Lucas T. Brady, Jeffrey Larson, Sven Leyffer, and Siqian Shen,

Quantum 7, 892 (2023).

Quantum control aims to manipulate quantum systems toward specific quantum states or desired operations. Designing highly accurate and effective control steps is vitally important to various…

Paper

Objective trajectories in hybrid classical-quantum dynamics

Jonathan Oppenheim, Carlo Sparaciari, Barbara Šoda, and Zachary Weller-Davies,

Quantum 7, 891 (2023).

Consistent dynamics which couples classical and quantum degrees of freedom exists, provided it is stochastic. This dynamics is linear in the hybrid state, completely positive and trace prese…

Paper

An Improved Sample Complexity Lower Bound for (Fidelity) Quantum State Tomography

Henry Yuen,

Quantum 7, 890 (2023).

We show that $\Omega(rd/\epsilon)$ copies of an unknown rank-$r$, dimension-$d$ quantum mixed state are necessary in order to learn a classical description with $1 – \epsilon$ fidelity. This improve…

Paper

Fluid fermionic fragments for optimizing quantum measurements of electronic Hamiltonians in the variational quantum eigensolver

Seonghoon Choi, Ignacio Loaiza, and Artur F. Izmaylov,

Quantum 7, 889 (2023).

Measuring the expectation value of the molecular electronic Hamiltonian is one of the challenging parts of the variational quantum eigensolver. A widely used strategy is to express the Hamil…

Paper

The Synthetic Hilbert Space of Laser-Driven Free-Electrons

Guy Braiman, Ori Reinhardt, Chen Mechel, Omer Levi, and Ido Kaminer,

Quantum 7, 888 (2023).

Recent advances in laser interactions with coherent free electrons have enabled to shape the electron's quantum state. Each electron becomes a superposition of energy levels on an infinite q…

Paper

Probing quantum entanglement from magnetic-sublevels populations: beyond spin squeezing inequalities

Guillem Müller-Rigat, Maciej Lewenstein, and Irénée Frérot,

Quantum 6, 887 (2022).

Spin squeezing inequalities (SSI) represent a major tool to probe quantum entanglement among a collection of few-level atoms, and are based on collective spin measurements and their fluctuat…

Paper

Solvable model of deep thermalization with distinct design times

Matteo Ippoliti and Wen Wei Ho,

Quantum 6, 886 (2022).

We study the emergence over time of a universal, uniform distribution of quantum states supported on a finite subsystem, induced by projectively measuring the rest of the system. Dubbed…

Paper

Half-integer vs. integer effects in quantum synchronization of spin systems

Ryan Tan, Christoph Bruder, and Martin Koppenhöfer,

Quantum 6, 885 (2022).

We study the quantum synchronization of a single spin driven by an external semiclassical signal for spin numbers larger than $S = 1$, the smallest system to host a quantum self-sustained osci…

Paper

Quantum speed limits on operator flows and correlation functions

Nicoletta Carabba, Niklas Hörnedal, and Adolfo del Campo,

Quantum 6, 884 (2022).

Quantum speed limits (QSLs) identify fundamental time scales of physical processes by providing lower bounds on the rate of change of a quantum state or the expectation value of an observabl…

Paper

Quantum Liouvillian exceptional and diabolical points for bosonic fields with quadratic Hamiltonians: The Heisenberg-Langevin equation approach

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

Quantum 6, 883 (2022).

Equivalent approaches to determine eigenfrequencies of the Liouvillians of open quantum systems are discussed using the solution of the Heisenberg-Langevin equations and the corresponding eq…

Category: Paper