Quantum

Paper

Fast simulation of quantum algorithms using circuit optimization

Gian Giacomo Guerreschi,

Quantum 6, 706 (2022).

Classical simulators play a major role in the development and benchmark of quantum algorithms and practically any software framework for quantum computation provides the option of running th…

Paper

Bending the rules of low-temperature thermometry with periodic driving

Jonas Glatthard and Luis A. Correa,

Quantum 6, 705 (2022).

There exist severe limitations on the accuracy of low-temperature thermometry, which poses a major challenge for future quantum-technological applications. Low-temperature sensitivity might…

Paper

Maximal entanglement increase with single-photon subtraction

Kun Zhang, Jietai Jing, Nicolas Treps, and Mattia Walschaers,

Quantum 6, 704 (2022).

Entanglement is an indispensable quantum resource for quantum information technology. In continuous-variable quantum optics, photon subtraction can increase the entanglement between Gaussian…

Paper

Unitary Selective Coupled-Cluster Method

Dmitry A. Fedorov, Yuri Alexeev, Stephen K. Gray, and Matthew Otten,

Quantum 6, 703 (2022).

Simulating molecules using the Variational Quantum Eigensolver method is one of the promising applications for NISQ-era quantum computers. Designing an efficient ansatz to represent the elec…

Paper

Entanglement Spectroscopy and probing the Li-Haldane Conjecture in Topological Quantum Matter

Torsten V. Zache, Christian Kokail, Bhuvanesh Sundar, and Peter Zoller,

Quantum 6, 702 (2022).

Topological phases are characterized by their entanglement properties, which is manifest in a direct relation between entanglement spectra and edge states discovered by Li and Haldane. We pr…

Paper

Eigenstate entanglement in integrable collective spin models

Meenu Kumari and Álvaro M. Alhambra,

Quantum 6, 701 (2022).

The average entanglement entropy (EE) of the energy eigenstates in non-vanishing partitions has been recently proposed as a diagnostic of integrability in quantum many-body systems. For it t…

Paper

Understanding and Improving Critical Metrology. Quenching Superradiant Light-Matter Systems Beyond the Critical Point

Karol Gietka, Lewis Ruks, and Thomas Busch,

Quantum 6, 700 (2022).

We carefully examine critical metrology and present an improved critical quantum metrology protocol which relies on quenching a system exhibiting a superradiant quantum phase transition beyo…

Paper

An Operational Environment for Quantum Self-Testing

Matthias Christandl, Nicholas Gauguin Houghton-Larsen, and Laura Mancinska,

Quantum 6, 699 (2022).

Observed quantum correlations are known to determine in certain cases the underlying quantum state and measurements. This phenomenon is known as $\textit{(quantum) self-testing}$. Self-testing…

Paper

The XYZ$^2$ hexagonal stabilizer code

Basudha Srivastava, Anton Frisk Kockum, and Mats Granath,

Quantum 6, 698 (2022).

We consider a topological stabilizer code on a honeycomb grid, the "XYZ$^2$" code. The code is inspired by the Kitaev honeycomb model and is a simple realization of a "matching code" discussed…

Paper

Back to sources – the role of losses and coherence in super-resolution imaging revisited

Stanislaw Kurdzialek,

Quantum 6, 697 (2022).

Photon losses are intrinsic for any translationally invariant optical imaging system with a non-trivial Point Spread Function, and the relation between the transmission factor and the cohere…

Paper

Optimal synthesis into fixed XX interactions

Eric C. Peterson, Lev S. Bishop, and Ali Javadi-Abhari,

Quantum 6, 696 (2022).

We describe an optimal procedure, as well as its efficient software implementation, for exact and approximate synthesis of two-qubit unitary operations into any prescribed discrete family of…

Paper

Activation of genuine multipartite entanglement: Beyond the single-copy paradigm of entanglement characterisation

Hayata Yamasaki, Simon Morelli, Markus Miethlinger, Jessica Bavaresco, Nicolai Friis, and Marcus Huber,

Quantum 6, 695 (2022).

Entanglement shared among multiple parties presents complex challenges for the characterisation of different types of entanglement. One of the most fundamental insights is the fact that some…

Paper

Time-Slicing Path-integral in Curved Space

Mingnan Ding and Xiangjun Xing,

Quantum 6, 694 (2022).

Path integrals constitute powerful representations for both quantum and stochastic dynamics. Yet despite many decades of intensive studies, there is no consensus on how to formulate them for…

Paper

Boundaries for the Honeycomb Code

Jeongwan Haah and Matthew B. Hastings,

Quantum 6, 693 (2022).

We introduce a simple construction of boundary conditions for the honeycomb code [1] that uses only pairwise checks and allows parallelogram geometries at the cost of modifying the bulk meas…

Paper

New techniques for bounding stabilizer rank

Benjamin Lovitz and Vincent Steffan,

Quantum 6, 692 (2022).

In this work, we present number-theoretic and algebraic-geometric techniques for bounding the stabilizer rank of quantum states. First, we refine a number-theoretic theorem of Moulton to exh…

Paper

Few-particle scattering from localized quantum systems in spatially structured bosonic baths

Rahul Trivedi, Kevin Fischer, Shanhui Fan, and Jelena Vuckovic,

Quantum 6, 691 (2022).

Understanding dynamics of localized quantum systems embedded in engineered bosonic environments is a central problem in quantum optics and open quantum system theory. We present a formalism…

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