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The quantum regression theorem states that the correlations of a system at two different times are governed by the same equations of motion as the temporal response of the average values. Such a relation provides a powerful framework for…

The formation of Bose condensates far from equilibrium can play an important role in our understanding of collision experiments of heavy nuclei or for the evolution of the early universe. In the relativistic quantum world particle number…

High Energy Physics - Phenomenology · Physics 2015-06-03 J. Berges , D. Sexty

We study the dynamics of two interacting Bose-Einstein condensates, by numerically solving two coupled Gross-Pitaevskii equations at zero temperature. We consider the case of a sudden transfer of atoms between two trapped states with…

Condensed Matter · Physics 2009-10-31 M. Modugno , F. Dalfovo , C. Fort , P. Maddaloni , F. Minardi

Theoretical considerations of Bell-inequality experiments usually assume identically prepared and independent pairs of particles. Here we consider pairs that exhibit both intra- and inter-pair entanglement. The pairs are taken from a large…

Quantum Physics · Physics 2009-12-17 S. Ashhab , Koji Maruyama , Caslav Brukner , Franco Nori

Entanglement is considered to be one of the most profound features of quantum mechanics. An entangled state of a system consisting of two subsystems cannot be described as a product of the quantum states of the two subsystems. In this sense…

Quantum Physics · Physics 2009-11-07 Brian Julsgaard , Alexander Kozhekin , Eugene S. Polzik

An ensemble consisting on systems of two entangled spin 1/2 particles, all of them in the same global quantum state, are considered. The two spins are measured, each of them, on a fixed direction, at two randomly selected measurement times.…

Quantum Physics · Physics 2015-03-06 Ramon Lapiedra , A. Pérez

We study possible scenarios for quantum non-demolition measurements using Bose-Einstein condensates. We show that the interactions between condensate atoms makes it possible to measure the atom number with minimal back action on the system.…

Soft Condensed Matter · Physics 2009-11-07 S. Choi , K. Burnett

We investigate the quantum interference between two Bose-Einstein condensates formed in small atomic samples composed of a few thousand atoms both by imposing Bose broken gauge symmetry from the outset and also using an explicit model of…

Condensed Matter · Physics 2009-10-28 E. M. Wright , T. Wong , M. J. Collett , S. M. Tan , D. F. Walls

In this paper, we consider N-level quantum angular momentum systems interacting with electromagnetic fields undergoing continuous-time measurements. We suppose unawareness of the initial state and physical parameters, entailing the…

Optimization and Control · Mathematics 2020-07-09 Weichao Liang , Nina H. Amini , Paolo Mason

We consider the effects of experimental imperfections on the problem of estimation-based feedback control of a trapped particle under continuous position measurement. These limitations violate the assumption that the estimator (i.e. filter)…

We use continuous, stochastic quantum trajectories within a framework of quantum state diffusion (QSD) to describe alternating measurements of two non-commuting observables. Projective measurement of an observable completely destroys memory…

Quantum Physics · Physics 2024-09-24 Sophia M. Walls , Ian J. Ford

We show that an analogue to the classical Einstein-de Haas effect can appear in ultracold dipolar Fermi gases. The anisotropic nature of dipole-dipole interactions can lead to a transfer of magnetization into orbital angular momentum.…

Quantum Gases · Physics 2017-01-31 Ulrich Ebling , Masahito Ueda

Oscillations of superconducting current between clockwise and counterclockwise directions in a flux qubit do not conserve the angular momentum of the qubit. To compensate for this effect the solid containing the qubit must oscillate in…

Superconductivity · Physics 2011-12-30 E. M. Chudnovsky , D. A. Garanin , M. F. O'Keeffe

The dynamics of a quantum anharmonic oscillator whose position is monitored by a Bose-Einstein condensate (BEC) trapped in a symmetric double well potential is studied. The (non-exponential) decoherence induced on the oscillator by the…

Quantum Physics · Physics 2014-10-29 D. Alonso , S. Brouard , D. Sokolovski

We analyze, analytically and numerically, the position, momentum, and in particular the angular-momentum variance of a Bose-Einstein condensate (BEC) trapped in a two-dimensional anisotropic trap for static and dynamic scenarios. The…

Quantum Gases · Physics 2019-11-04 Ofir E. Alon

Quantum reservoir computing is a type of machine learning in which the high-dimensional Hilbert space of quantum systems contributes to performance. In this study, we employ the Bose-Einstein condensate of dilute atomic gas as a reservoir…

Quantum Gases · Physics 2024-08-23 Yuki Kurokawa , Junichi Takahashi , Yoshiya Yamanaka

The Einstein-Podolski-Rosen paradox highlights several strange properties of quantum mechanics including the super position of states, the non locality and its limitation to determine an experiment only statistically. Here, this well known…

Quantum Physics · Physics 2017-09-13 Roland Riek

In this article we propose an alternate model for the so called {\it protective measurements}, more appropriately {\it adiabatic measurements} of a spin 1/2 system where the {\it apparatus} is also a quantum system with a {\em finite…

Quantum Physics · Physics 2007-05-23 Anirban Das , N. D. Hari Dass

Continuously measured interacting quantum systems almost invariably heat, causing loss of quantum coherence. Here, we study Bose-Einstein condensates (BECs) subject to repeated weak measurement of the atomic density and describe several…

Quantum Gases · Physics 2023-06-28 Evan P. Yamaguchi , Hilary M. Hurst , I. B. Spielman

We study an analog quantum simulator coupled to a reservoir with a known spectral density. The reservoir perturbs the quantum simulation by causing decoherence. The simulator is used to measure an operator average, which cannot be…