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We investigate the feasibility of performing quantum non-demolition (QND) measurements in relativistic quantum systems, using the one-dimensional Dirac oscillator as a specific example. We derive general expressions for its QND observables…

Quantum Physics · Physics 2021-08-12 Wei Sun , Keye Zhang , Pierre Meystre , Weiping Zhang

Quasiprobability distributions (QDs) in open quantum systems are investigated for $SU(2)$, spin like systems, having relevance to quantum optics and information. In this work, effect of both quantum non-demolition (QND) and dissipative open…

Quantum Physics · Physics 2022-06-10 Kishore Thapliyal , Subhashish Banerjee , Anirban Pathak , S. Omkar , V. Ravishankar

For a (classically) integrable quantum mechanical system with two degrees of freedom, the functional dependence $\hat{H}=H_Q(\hat{J}_1,\hat{J}_2)$ of the Hamiltonian operator on the action operators is analyzed and compared with the…

Chaotic Dynamics · Physics 2009-10-31 Vyacheslav V. Stepanov , Gerhard Muller

An algebraic method has been developed which allows one to engineer several energy levels including the low-energy subspace of interacting spin systems. By introducing ancillary qubits, this approach allows k-body interactions to be…

Quantum Physics · Physics 2008-07-29 J. D. Biamonte

Quantum nondemolition (QND) measurements of photons is a much pursued endeavor in the field of quantum optics and quantum information processing. Here we propose a novel hybrid optoelectromechanical platform that integrates a cavity system…

Mesoscale and Nanoscale Physics · Physics 2021-01-04 Junjie Liu , Hsing-Ta Chen , Dvira Segal

We show that quantum nondemolition (QND) measurements can be used to realize measurement-based imaginary time evolution. In our proposed scheme, repeated weak QND measurements are used to estimate the energy of a given Hamiltonian. Based on…

We study the dynamics of the Gaudin magnet ("central-spin model") using machine-learning methods. This model is of practical importance, e.g., for studying non-Markovian decoherence dynamics of a central spin interacting with a large bath…

Quantum Physics · Physics 2024-05-17 Victor Wei , Alev Orfi , Felix Fehse , W. A. Coish

We analyze the dynamics of entanglement in a two-qubit system interacting with an initially squeezed thermal environment via a quantum nondemolition system-reservoir interaction, with the system and reservoir assumed to be initially…

Quantum Physics · Physics 2015-05-13 Subhashish Banerjee , V. Ravishankar , R. Srikanth

Planar squeezed states, i.e. quantum states which are squeezed in two orthogonal spin components, have recently attracted attention due to their applications in atomic interferometry and quantum information [Q. Y. He et al, New J. Phys. 14,…

Quantum Physics · Physics 2015-06-12 Graciana Puentes , Giorgio Colangelo , Robert J. Sewell , Morgan W. Mitchell

Quantum Brownian oscillator model (QBM), in the Fock-space representation, can be viewed as a multi-level spin-boson model. At sufficiently low temperature, the oscillator degrees of freedom are dynamically reduced to the lowest two levels…

Quantum Physics · Physics 2009-11-10 K. Shiokawa , B. L. Hu

The electronic spin degrees of freedom in semiconductors typically have decoherence times that are several orders of magnitude longer than other relevant timescales. A solid-state quantum computer based on localized electron spins as qubits…

Quantum Physics · Physics 2007-05-23 A. Imamoglu , D. D. Awschalom , G. Burkard , D. P. DiVincenzo , D. Loss , M. Sherwin , A. Small

We study, with the use of numerical integration, a noncommutative extension of a quantum-theoretic model (an alternative to the semiclassical Brillouin function), recently presented by Brody and Hughston and, independently, Slater, for the…

Quantum Physics · Physics 2007-05-23 Paul B. Slater

This is a review paper concerned with the global consistency of the quantum dynamics of non-commutative systems. Our point of departure is the theory of constrained systems, since it provides a unified description of the classical and…

High Energy Physics - Theory · Physics 2015-05-13 F. S. Bemfica , H. O. Girotti

The paper presents an analysis of entangling and nonlocal operations in a quantum nondemolition (QND) interaction between multimode light with orbital angular momentum and an atomic ensemble. A protocol consists of two QND operations with…

Quantum Physics · Physics 2024-10-17 E. A. Vashukevich , T. Yu. Golubeva

Algorithmic cooling can be used to find correlated states of many-body quantum systems. It is based on quantum circuits that perform nonunitary operations, whose implementation can be challenging on near-term quantum computers. In this work…

The dynamics and decoherence of an electronic spin-1/2 qubit coupled to a bath of nuclear spins via hyperfine interactions in a quantum dot is studied. We show how exact results from the integrable solution can be used to understand the…

Strongly Correlated Electrons · Physics 2010-10-22 Michael Bortz , Sebastian Eggert , Christian Schneider , Robert Stubner , Joachim Stolze

It is possible to simulate the dynamics of a single spin-$1/2$ ($\mathsf{PT~}$ symmetric) system by conveniently embedding it into a subspace of a larger Hilbert space with unitary dynamics. Our goal is to formulate a many body…

Quantum Physics · Physics 2021-08-04 Anant V. Varma , Sourin Das

Two hallmarks of quantum non-demolition (QND) measurement are the ensemble-level conservation of the expectation value of the measured observable $A$ and the eventual, inevitable collapse of the system into some eigenstate of $A$. This…

Quantum Physics · Physics 2025-05-07 Carter Swift , Nandini Trivedi

Quantum nondemolition (QND) measurements are a precious resource for quantum information processing. Repetitive QND measurements can boost the fidelity of qubit preparation and measurement, even when the underlying single-shot measurements…

Quantum simulation of non-Markovian open quantum dynamics is essential but challenging for standard quantum computers due to their non-Hermitian nature, leading to non-unitary evolution, and the limitations of available quantum resources.…

Quantum Physics · Physics 2026-01-12 Yukai Guo , Xing Gao