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Nonpositive-transpose entanglement and bound entanglement: From distillability sets to inequalities and multivariable insights

PRA: Quantum information - Mon, 2024-07-01 12:00

Author(s): Si-Yuan Qi, Geni Gupur, Yu-Chun Wu, and Guo-Ping Guo

Equivalence between positive partial transpose (PPT) entanglement and bound entanglement is a long-standing open problem in quantum information theory. Limited progress has been made so far, even on the seemingly simple case of the bound entanglement of Werner states. The primary challenge is to giv…


[Phys. Rev. A 110, 012406] Published Mon Jul 01, 2024

Categories: Journals, Physics

Exploring many-body interactions through quantum Fisher information

PRA: Quantum information - Mon, 2024-07-01 12:00

Author(s): Paweł Cieśliński, Paweł Kurzyński, Tomasz Sowiński, Waldemar Kłobus, and Wiesław Laskowski

The investigation of many-body interactions holds significant importance for both quantum foundations and information. Hamiltonians coupling multiple particles at once, beyond other applications, can lead to faster entanglement generation, multiqubit gate implementation, and improved error correctio…


[Phys. Rev. A 110, 012407] Published Mon Jul 01, 2024

Categories: Journals, Physics

Quadrature coherence scale of linear combinations of Gaussian functions in phase space

PRA: Quantum information - Mon, 2024-07-01 12:00

Author(s): Anaelle Hertz, Aaron Z. Goldberg, and Khabat Heshami

The quadrature coherence scale (QCS) is a recently introduced measure that was shown to be an efficient witness of nonclassicality. It takes a simple form for pure and Gaussian states, but a general expression for mixed states tends to be prohibitively unwieldy. In this paper we introduce a method f…


[Phys. Rev. A 110, 012408] Published Mon Jul 01, 2024

Categories: Journals, Physics

Effect of alternating layered <i>Ansäatze</i> on trainability of projected quantum kernels

PRA: Quantum information - Mon, 2024-07-01 12:00

Author(s): Yudai Suzuki and Muyuan Li

Quantum kernel methods have been actively examined from both theoretical and practical perspectives due to the potential of quantum advantage in machine learning tasks. Despite a provable advantage of fine-tuned quantum kernels for specific problems, widespread practical usage of quantum kernel meth…


[Phys. Rev. A 110, 012409] Published Mon Jul 01, 2024

Categories: Journals, Physics

Nonclassical resource for continuous-variable telecloning with non-Gaussian advantage

PRA: Quantum information - Mon, 2024-07-01 12:00

Author(s): Sudipta Das, Rivu Gupta, Himadri Shekhar Dhar, and Aditi Sen(De)

The telecloning protocol distributes quantum states from a single sender to multiple receivers via a shared entangled state by exploiting the notions of teleportation and approximate cloning. We investigate the optimal telecloning fidelities obtained using both Gaussian and non-Gaussian shared resou…


[Phys. Rev. A 110, 012410] Published Mon Jul 01, 2024

Categories: Journals, Physics

Large Deviation Full Counting Statistics in Adiabatic Open Quantum Dynamics

Author(s): Paulo J. Paulino, Igor Lesanovsky, and Federico Carollo

The state of an open quantum system undergoing an adiabatic process evolves by following the instantaneous stationary state of its time-dependent generator. This observation allows one to characterize, for a generic adiabatic evolution, the average dynamics of the open system. However, information a…


[Phys. Rev. Lett. 132, 260402] Published Fri Jun 28, 2024

Categories: Journals, Physics

Catalytic Advantage in Otto-like Two-Stroke Quantum Engines

Author(s): Marcin Łobejko, Tanmoy Biswas, Paweł Mazurek, and Michał Horodecki

We demonstrate how to incorporate a catalyst to enhance the performance of a heat engine. Specifically, we analyze efficiency in one of the simplest engine models, which operates in only two strokes and comprises of a pair of two-level systems, potentially assisted by a d-dimensional catalyst. When …


[Phys. Rev. Lett. 132, 260403] Published Fri Jun 28, 2024

Categories: Journals, Physics

Twin-Field Quantum Key Distribution with Local Frequency Reference

Author(s): Jiu-Peng Chen, Fei Zhou, Chi Zhang, Cong Jiang, Fa-Xi Chen, Jia Huang, Hao Li, Li-Xing You, Xiang-Bin Wang, Yang Liu, Qiang Zhang, and Jian-Wei Pan

Twin-field quantum key distribution (TFQKD) overcomes the linear rate-loss limit, which promises a boost of secure key rate over long distance. However, the complexity of eliminating the frequency differences between the independent laser sources hinders its practical application. We analyzed and de…


[Phys. Rev. Lett. 132, 260802] Published Fri Jun 28, 2024

Categories: Journals, Physics

Giant Clams Are Models of Solar-Energy Efficiency

APS Physics - Fri, 2024-06-28 12:00

Author(s): Mark Buchanan

A theoretical model for the illumination of photosynthesizing algae in giant clams suggests principles for high efficiency collection of sunlight.


[Physics 17, 106] Published Fri Jun 28, 2024

Categories: Physics

Quantum illumination using non-Gaussian states with conditional measurements

PRA: Quantum information - Fri, 2024-06-28 12:00

Author(s): Huan Zhang, Ying Xia, Wei Ye, Shoukang Chang, and Zeyang Liao

Quantum illumination is a quantum sensing protocol primarily used for object detection, which aims to detect the presence of a target with low reflectivity in the free space using quantum light fields. Here we investigate a quantum illumination scheme using an entangled light source by performing no…


[Phys. Rev. A 109, 062440] Published Fri Jun 28, 2024

Categories: Journals, Physics

Implementing fault-tolerant non-Clifford gates using the [[8,3,2]] color code

PRA: Quantum information - Fri, 2024-06-28 12:00

Author(s): Daniel Honciuc Menendez, Annie Ray, and Michael Vasmer

Quantum computers promise to solve problems that are intractable for classical computers, but qubits are vulnerable to many sources of error, limiting the depth of the circuits that can be reliably executed on today's quantum hardware. Quantum error correction has been proposed as a solution to this…


[Phys. Rev. A 109, 062438] Published Fri Jun 28, 2024

Categories: Journals, Physics

Cooper-pair beam splitter as a feasible source of entangled electrons

PRA: Quantum information - Fri, 2024-06-28 12:00

Author(s): B. Sharmila, F. M. Souza, H. M. Vasconcelos, and L. Sanz

We investigate the generation of an entangled electron pair emerging from a system composed of two quantum dots attached to a superconductor Cooper-pair beam splitter. We take into account three processes: crossed Andreev reflection, cotunneling, and Coulomb interaction. Together, these processes pl…


[Phys. Rev. A 109, 062439] Published Fri Jun 28, 2024

Categories: Journals, Physics

Catalysis in quantum information theory

Reviews of Modern Physics - Thu, 2024-06-27 12:00

Author(s): Patryk Lipka-Bartosik, Henrik Wilming, and Nelly H. Y. Ng

A branch of quantum information is concerned with transformations that are possible given certain resources: for example, quantum teleportation moves a quantum state from one place to another, aided by entanglement and classical communication. Certain other tasks are provably impossible. But, as surveyed in this review, a surprising fact is that some tasks become possible if another quantum state is present, even if this state is returned untouched at the end of the task. This “quantum catalysis” enables a large variety of interesting tasks, with applications ranging from cryptography to thermodynamics.


[Rev. Mod. Phys. 96, 025005] Published Thu Jun 27, 2024

Categories: Journals, Physics

Agnostic Phase Estimation

Author(s): Xingrui Song, Flavio Salvati, Chandrashekhar Gaikwad, Nicole Yunger Halpern, David R. M. Arvidsson-Shukur, and Kater Murch

Quantum sensing can benefit from entanglement protocols that can be interpreted as allowing qubits to go backward in time to choose an optimal initial state.


[Phys. Rev. Lett. 132, 260801] Published Thu Jun 27, 2024

Categories: Journals, Physics

The Most Precise Value of the Top-Quark Mass to Date

APS Physics - Thu, 2024-06-27 12:00

Author(s): Nikhil Karthik

Researchers at CERN have significantly increased the precision of the measured value of the top-quark mass, a key input for making standard-model calculations.


[Physics 17, s57] Published Thu Jun 27, 2024

Categories: Physics

Measuring Qubits with “Time Travel” Protocol

APS Physics - Thu, 2024-06-27 12:00

Author(s): Michael Schirber

Quantum sensing can benefit from entanglement protocols that can be interpreted as allowing qubits to go backward in time to choose an optimal initial state.


[Physics 17, s76] Published Thu Jun 27, 2024

Categories: Physics

Unitary averaging with fault and loss tolerance

PRA: Quantum information - Thu, 2024-06-27 12:00

Author(s): Ryan J. Marshman, Deepesh Singh, Timothy C. Ralph, and Austin P. Lund

We consider the impact of the unitary-averaging framework on single- and two-mode linear optical gates. We demonstrate that this allows a trade-off between the probability of success and gate fidelity, with perfect fidelity gates being achievable for a finite decrease in the probability of success, …


[Phys. Rev. A 109, 062436] Published Thu Jun 27, 2024

Categories: Journals, Physics

Combining matrix product states and noisy quantum computers for quantum simulation

PRA: Quantum information - Thu, 2024-06-27 12:00

Author(s): Baptiste Anselme Martin, Thomas Ayral, François Jamet, Marko J. Rančić, and Pascal Simon

Matrix product states (MPSs) and matrix product operators (MPOs) have been proven to be a powerful tool to study quantum many-body systems but are restricted to moderately entangled states as the number of parameters scales exponentially with the entanglement entropy. While MPSs can efficiently find…


[Phys. Rev. A 109, 062437] Published Thu Jun 27, 2024

Categories: Journals, Physics

Computing Quantum Mean Values in the Deep Chaotic Regime

Author(s): Gabriel M. Lando, Olivier Giraud, and Denis Ullmo

We study the time evolution of mean values of quantum operators in a regime plagued by two difficulties: the smallness of ℏ and the presence of strong and ubiquitous classical chaos. While numerics become too computationally expensive for purely quantum calculations as ℏ→0, methods that take advanta…


[Phys. Rev. Lett. 132, 260401] Published Wed Jun 26, 2024

Categories: Journals, Physics

Mechanical Coupling to Spin Qubits

APS Physics - Wed, 2024-06-26 12:00

Author(s): Michael Schirber

A vibrating nanobeam could be used to share information between distant solid-state spin qubits, potentially allowing use of these qubits in complex computations.


[Physics 17, s71] Published Wed Jun 26, 2024

Categories: Physics
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