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If only limited control over a multiparticle quantum system is available, a viable method to characterize correlations is to perform random measurements and consider the moments of the resulting probability distribution. We present…

Quantum Physics · Physics 2021-04-23 Satoya Imai , Nikolai Wyderka , Andreas Ketterer , Otfried Gühne

We consider entanglement distillation with noisy operations in which quantum measurements that constitute a general quantum operation are particularly noisy. We present a protocol for purifying noisy measurements and show that imperfect…

Quantum Physics · Physics 2025-02-11 Jaemin Kim , Jiyoung Yun , Joonwoo Bae

We investigate the generation of quantum states and unitary operations that are ``random'' in certain respects. We show how to use such states to estimate the average fidelity, an important measure in the study of implementations of quantum…

Quantum Physics · Physics 2007-05-23 Christoph Dankert

Noise characterization methods such as randomized benchmarking (RB) are critical for the development of scalable quantum computers. Modern RB protocols for multiqubit systems extract physically relevant error rates by exploiting the…

Quantum Physics · Physics 2026-04-15 Yale Fan , Riley Murray , Thaddeus D. Ladd , Kevin Young , Robin Blume-Kohout

Entanglement distillation is the process of converting noisy entangled states into maximally entangled pure states via local operations and classical communication. A long-standing, unresolved question is which entangled states are amenable…

Quantum Physics · Physics 2026-04-28 Tobias C. Sutter , Christopher Popp , Beatrix C. Hiesmayr

High-fidelity entanglement shared between distant quantum systems is an essential resource for quantum communication and computation. Entanglement distillation addresses this need by converting multiple noisy Bell pairs into fewer…

Quantum Physics · Physics 2025-03-14 Shoham Jacoby , Rotem Arnon-Friedman , Serge Rosenblum

An approach to quantum random number generation based on unambiguous quantum state discrimination (USD) is developed. We consider a prepare-and-measure protocol, where two non-orthogonal quantum states can be prepared, and a measurement…

An exact reduced-density-operator for the output quantum states in time-convolutionless form was derived by solving the quantum Liouville equation which governs the dynamics of a noisy quantum channel by using a projection operator method…

Quantum Physics · Physics 2009-10-31 D. Ahn , J. H. Oh , K. Kimm , S. W. Hwang

We consider the time evolution of a quantized field in backgrounds that violate the vacuum stability (particle-creating backgrounds). Our aim is to study the exact form of the final quantum state (the density operator at a final instant of…

High Energy Physics - Theory · Physics 2011-08-26 S. P. Gavrilov , D. M. Gitman , J. L. Tomazelli

We present a physical- and link-level design for the creation of entangled pairs to be used in quantum repeater applications where one can control the noise level of the initially distributed pairs. The system can tune dynamically, trading…

Quantum Physics · Physics 2009-11-13 W. J. Munro , R. Van Meter , Sebastien G. R. Louis , Kae Nemoto

Generating entangled states is one of the most important tasks in quantum information technology. However, in reality any entanglement generator must contain some characteristic uncertainty, and as a result the produced entangled state…

Quantum Physics · Physics 2019-02-20 Kensuke Gallock Yoshimura , Naoki Yamamoto

We describe a method for generating entanglement between two spatially separated dipoles coupled to optical micro-cavities. The protocol works even when the dipoles have different resonant frequencies and radiative lifetimes. This method is…

Quantum Physics · Physics 2009-11-13 Deepak Sridharan , Edo Waks

Producing quantum states at random has become increasingly important in modern quantum science, with applications both theoretical and practical. In particular, ensembles of such randomly-distributed, but pure, quantum states underly our…

The idea of exploiting maximally-entangled states as a resource lies at the core of several modalities of quantum information processing, including secure quantum communication, quantum computation, and quantum sensing. However, due to…

Quantum Physics · Physics 2023-05-31 Andrea Rodriguez-Blanco , K. Birgitta Whaley , Alejandro Bermudez

We present a protocol that allows the estimation of any density matrix element for continuous-variable quantum states, without resorting to the complete reconstruction of the full density matrix. The algorithm adaptatively discretizes the…

Quantum Physics · Physics 2024-09-25 Virginia Feldman , Ariel Bendersky

Restricted Boltzmann machines (RBMs) are a class of neural networks that have been successfully employed as a variational ansatz for quantum many-body wave functions. Here, we develop an analytic method to study quantum many-body spin…

Quantum Physics · Physics 2022-10-06 Xiao-Qi Sun , Tamra Nebabu , Xizhi Han , Michael O. Flynn , Xiao-Liang Qi

High-dimensional quantum entanglement is an essential resource in quantum technology since it provides benefits in increasing the information capacity and processing speed. Thus, the controlled harnessing of high-dimensional entanglement…

Quantum Physics · Physics 2024-12-30 Ling Hong , Yuning Zhang , Yuanyuan Chen , Lixiang Chen

Near-term quantum computation holds potential across multiple application domains. However, imperfect preparation and evolution of states due to algorithmic and experimental shortcomings, characteristic in the near-term implementation,…

Entanglement distillation is a fundamental task in quantum information processing. It not only extracts entanglement out of corrupted systems but also leads to protecting systems of interest against intervention with environment. In this…

Quantum Physics · Physics 2017-07-11 Jinho Chang , Joonwoo Bae , Younghun Kwon

Quantum systems out of equilibrium are presently a subject of active research, both in theoretical and experimental domains. In this work we consider time-periodically modulated quantum systems which are in contact with a stationary…

Quantum Gases · Physics 2017-12-06 V. Volokitin , A. Liniov , I. Meyerov , M. Hartmann , M. Ivanchenko , P. Hänggi , S. Denisov