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A long-lived prethermal state may emerge upon a sudden quench of a quantum system. In this paper, we study a quantum quench of an initial {\it critical} state, and show that the resulting prethermal state exhibits a genuinely quantum and…

Quantum Gases · Physics 2017-09-15 Mohammad F. Maghrebi

It is shown that, despite strong nonlinearity, entanglement of formation of two-qubit state can be measured without prior state reconstruction. Collective measurements on small number of copies are provided that allow to determine quantum…

Quantum Physics · Physics 2007-05-23 Pawel Horodecki

Bell's theorem implies that any completion of quantum mechanics which uses hidden variables (that is, preexisting values of all observables) must be nonlocal in the Einstein sense. This customarily indicates that knowledge of the hidden…

Quantum Physics · Physics 2021-05-18 Avishy Carmi , Eliahu Cohen , Lorenzo Maccone , Hrvoje Nikolic

Quantum thermodynamic process involves manipulating and controlling quantum states to extract energy or perform computational tasks with high efficiency. There is still no efficientgeneral method to theoretically quantify the effect of the…

Quantum Physics · Physics 2024-06-21 Ming-Xing Luo

We establish a sharp quantum advantage in determining the parity (even/odd) of an unknown permutation applied to any number $n \ge 3$ of particles. Classically, this is impossible with fewer than $n$ labels, being that the success is…

Determining whether a quantum state is separable or entangled is a problem of fundamental importance in quantum information science. It has recently been shown that this problem is NP-hard. There is a highly inefficient `basic algorithm'…

Quantum Physics · Physics 2009-11-10 L. M. Ioannou , B. C. Travaglione , D. Cheung , A. K. Ekert

Quantum computing offers the promise of revolutionizing quantum chemistry by enabling the solution of chemical problems for substantially less computational cost. While most demonstrations of quantum computation to date have focused on…

Chemical Physics · Physics 2026-05-13 Alan Bidart , Prateek Vaish , Tilas Kabengele , Yaoqi Pang , Yuan Liu , Brenda M. Rubenstein

Spectral homodyne detection, a widely used technique for measuring quantum properties of light beams, cannot retrieve all the information needed to reconstruct the quantum state of spectral field modes. We show that full quantum state…

Quantum Machine Learning(QML) is developed by combining quantum mechanics principles with classical machine learning techniques in a hybrid framework that can give faster, exponential, more efficient power of quantum computing with the data…

Quantum Physics · Physics 2026-01-27 Pallab Biswas , Tamal Maity

It is a fundamental principle of quantum theory that an unknown state cannot be copied or, as a consequence, an unknown optical signal cannot be amplified deterministically and perfectly. Here we describe a protocol that provides…

Quantum Physics · Physics 2013-11-25 Electra Eleftheriadou , Stephen M. Barnett , John Jeffers

We consider the problem of deterministically cloning quantum channels with respect to the best attainable rate and the highest quality, so-called optimal cloning. We demonstrate that cloning quantum states is, in-fact, equivalent to cloning…

The experimental violation of Bell inequalities using spacelike separated measurements precludes the explanation of quantum correlations through causal influences propagating at subluminal speed. Yet, any such experimental violation could…

Quantum computing promises exponential speed-ups for important simulation and optimization problems. It also poses new CAD problems that are similar to, but more challenging, than the related problems in classical (non-quantum) CAD, such as…

Quantum Physics · Physics 2011-11-04 George F. Viamontes , Igor L. Markov , John P. Hayes

In this work, a theoretical generalization of Lloyd's quantum illumination to signal beams described by two entangled photon states is developed. It is shown that the new protocol offers a method to find the range of the target, reduces the…

Quantum Physics · Physics 2021-09-21 Ricardo Gallego Torromé , Nadya Ben Bekhti-Winkel , Peter Knott

In a recent paper [Phys.~Rev.~A {\bf 91}, 053844 (2015)], Mukamel and Dorfman compare spectroscopies performed with classical vs.~quantum light, and conclude that \textit{nonlinear} quantum-spectroscopy signals cannot be obtained from…

Mesoscale and Nanoscale Physics · Physics 2015-07-08 M. Kira , S. W. Koch , S. T. Cundiff

We show that information in quantum memory can be erased and recovered perfectly if it is necessary. That the final states of environment are completely determined by the initial states of the system allows that an easure operation can be…

Quantum Physics · Physics 2009-11-10 Qing-Yu Cai

A quantum seal is a way of encoding a classical message into quantum states, so that everybody can read the message error-free, but at the same time the sender and all intended readers who have some prior knowledge of the quantum seal, can…

Quantum Physics · Physics 2007-05-23 H. Bechmann-Pasquinucci

Stimulated emission is shown to be robust in stars. Through Bose enhancement this produces quantum states of aligned, monochromatic photons similar to a laser. The probability of creating such states is computed. We show that from the solar…

High Energy Physics - Phenomenology · Physics 2023-09-06 Arjun Berera , Jaime Calderón-Figueroa , Liang Chen , Thomas W. Kephart

Over the past decade quantum information theory has developed into a vigorous field of research despite the fact that quantum information, as a precise concept, is undefined. Indeed the very idea of viewing quantum states as carriers of…

Quantum Physics · Physics 2007-05-23 Richard Jozsa

When a light bulb is turned on, light moves away from it at speed $c$, by definition. When light from this bulb illuminates a surface, however, this illumination front is not constrained to move at speed $c$. A simple proof is given that…

Popular Physics · Physics 2016-06-22 Robert J. Nemiroff , Qi Zhong , Elias Lilleskov