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We perform a phase-space analysis of strong-field enhanced ionisation in molecules, with emphasis on quantum-interference effects. Using Wigner quasi-probability distributions and the quantum Liouville equation, we show that the momentum…

Atomic Physics · Physics 2019-07-30 H. Chomet , D. Sarkar , C. Figueira de Morisson Faria

We define the Wigner entropy of a quantum state as the differential Shannon entropy of the Wigner function of the state. This quantity is properly defined only for states that possess a positive Wigner function, which we name…

Quantum Physics · Physics 2022-01-03 Zacharie Van Herstraeten , Nicolas J. Cerf

Probing signatures of anomalous interactions of the Higgs boson with pairs of weak vector bosons is an important goal of an $e^+e^-$ collider commissioned as a Higgs factory. We perform a detailed analysis of such potential of a collider…

High Energy Physics - Phenomenology · Physics 2015-03-17 Gilad Amar , Shankha Banerjee , Stefan von Buddenbrock , Alan S. Cornell , Tanumoy Mandal , Bruce Mellado , Biswarup Mukhopadhyaya

The readings of a highly inaccurate "weak" quantum meter, employed to determine the value of a dichotomous variable $S$ without destroying the interference between the alternatives,may take arbitrary values. We show that the expected values…

Quantum Physics · Physics 2015-09-17 D. Sokolovski

Within a plane-wave approximation in scattering, an incoming wave packet's Wigner function stays everywhere positive, which obscures such purely quantum phenomena as non-locality and entanglement. With the advent of the electron microscopes…

Quantum Physics · Physics 2017-11-01 Dmitry V. Karlovets , Valeriy G. Serbo

Starting with the quasi-Bell states of the qubit-oscillator system, we obtain time evolution of the density matrix under the adiabatic approximation. The composite density matrix leads to, via partial tracing of the qubit degree of freedom,…

Quantum Physics · Physics 2015-02-11 R. Chakrabarti , B. Virgin Jenisha

We estimate the quantum state of a light beam from results of quantum homodyne measurements performed on identically prepared pulses. The state is represented through the Wigner function, a ``quasi-probability density'' on $\mathbb{R}^{2}$…

Statistics Theory · Mathematics 2011-06-23 Madalin Guta , Luis Artiles

We characterize the energetic footprint of a two-qubit quantum gate from the perspective of non-equilibrium quantum thermodynamics. We experimentally reconstruct the statistics of energy and entropy fluctuations following the implementation…

A relation is obtained between weak values of quantum observables and the consistency criterion for histories of quantum events. It is shown that ``strange'' weak values for projection operators (such as values less than zero) always…

Quantum Physics · Physics 2007-05-23 R. E. Kastner

For systems whose classical dynamics is chaotic, it is generally believed that the local statistical properties of the quantum energy levels are well described by Random Matrix Theory. We present here two counterexamples - the hydrogen atom…

chao-dyn · Physics 2009-10-28 Jakub Zakrzewski , Karine Dupret , Dominique Delande

Discriminating between quantum computing architectures that can provide quantum advantage from those that cannot is of crucial importance. From the fundamental point of view, establishing such a boundary is akin to pinpointing the resources…

Quantum Physics · Physics 2021-03-23 Laura García-Álvarez , Cameron Calcluth , Alessandro Ferraro , Giulia Ferrini

It is shown that weight operator of a composite quantum body in a weak external gravitational field in the post-Newtonian approximation of the General Relativity does not commute with its energy operator, taken in the absence of the field.…

General Relativity and Quantum Cosmology · Physics 2012-05-15 Andrei Lebed

Quantum weak energy inequalities (QWEI) provide state-independent lower bounds on averages of the renormalised energy density of a quantum field. We derive QWEIs for the electromagnetic and massive spin-one fields in globally hyperbolic…

General Relativity and Quantum Cosmology · Physics 2009-11-10 Christopher J. Fewster , Michael J. Pfenning

Simplest models of two- and three-terminal Quantum Quantum Gates are suggested in form of a quantum ring with few one-dimensional quantum wires attached to it and several point-wise govering electrodes inside the ring which are charged by a…

Condensed Matter · Physics 2007-05-23 S. Avdonin , N. Bagraev , A. Mikhailova , B. Pavlov

We describe the implementation of weak quantum measurements in superconducting qubits, focusing specifically on transmon type devices in the circuit quantum electrodynamics architecture. To access this regime, the readout cavity is probed…

Quantum Physics · Physics 2015-07-29 K. W. Murch , R. Vijay , I. Siddiqi

Non-Gaussian quantum states, described by negative valued Wigner functions, are important both for fundamental tests of quantum physics and for emerging quantum information technologies. However, they are vulnerable to dissipation. It is…

Quantum Physics · Physics 2022-01-11 B. Nugmanov , N. Zunikov , F. Ya. Khalili

We show that the vacuum (zero-point) energy of a low-temperature quantum liquid is a variable property which changes with the state of the system, in notable contrast to the static vacuum energy in solids commonly considered. We further…

Statistical Mechanics · Physics 2016-04-07 K. Trachenko , V. V. Brazhkin

We analyze energy exchanges between a qubit and a resonant field propagating in a waveguide. The joint dynamics is analytically solved within a repeated interaction model. The work received by the qubit is defined as the unitary component…

Quantum Physics · Physics 2021-09-29 Maria Maffei , Patrice A. Camati , Alexia Auffèves

Quantum Mechanical weak values are an interference effect measured by the cross-Wigner transform W({\phi},{\psi}) of the post-and preselected states, leading to a complex quasi-distribution {\rho}_{{\phi},{\psi}}(x,p) on phase space. We…

Mathematical Physics · Physics 2015-06-03 Maurice de Gosson , Serge de Gosson

The Wigner function of quantum systems is an effective instrument to construct the approximate classical description of the systems for which the classical approximation is possible. During the last time, the Wigner function formalism is…

Quantum Physics · Physics 2009-11-10 Constantin V. Usenko