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An adapted representation of quantum mechanics sheds new light on the relationship between quantum states and classical states. In this approach the space of quantum states splits into a product of the state space of classical mechanics and…

High Energy Physics - Theory · Physics 2021-04-14 Christoph Nölle

Constructing a classical mechanical system associated with a given quantum mechanical one, entails construction of a classical phase space and a corresponding Hamiltonian function from the available quantum structures and a notion of…

General Relativity and Quantum Cosmology · Physics 2008-11-26 Ghanashyam Date

We show that quantum mechanics can be represented as an asymptotic projection of statistical mechanics of classical fields. Thus our approach does not contradict to a rather common opinion that quantum mechanics could not be reduced to…

Quantum Physics · Physics 2009-11-11 Andrei Khrennikov

By employing the Naimark dilation, we establish a fundamental connection between non-Hermitian quantum sensing and post-selected measurements. The sensitivity of non-Hermitian quantum sensors is determined by the effective quantum Fisher…

Quantum Physics · Physics 2025-05-13 Neng Zeng , Tao Liu , Keyu Xia , Yu-Ran Zhang , Franco Nori

We report on a time scaling technique to enhance the performances of quantum protocols in non-Hermitian systems. The considered time scaling involves no extra-couplings and yields a significant enhancement of the quantum fidelity for a…

Quantum Physics · Physics 2021-12-08 F. Impens , F. M. D'Angelis , F. A. Pinheiro , D. Guéry-Odelin

We propose a method for precision statistical control of quantum processes based on superconductor phase qubits. Using the universal quantum tomography method, we provide a detailed analysis of accuracy of tomography for a 2-qubit gate…

Quantum Physics · Physics 2017-07-26 Yu. I. Bogdanov , S. A. Nuyanzin

In this project we examine several different quantum key distribution protocols which we divide into ones utilizing qubits whose Hilbert spaces are two dimensional and ones whose Hilbert space dimension is greater than two, these units of…

Quantum Physics · Physics 2024-02-05 Yuval Idan , Avihai Didi

We present a measurement protocol for a flux qubit coupled to a dc-Superconducting QUantum Interference Device (SQUID), representative of any two-state system with a controllable coupling to an harmonic oscillator quadrature, which consists…

Mesoscale and Nanoscale Physics · Physics 2008-08-18 I. Serban , B. L. T. Plourde , F. K. Wilhelm

The temporal evolution of a quantum system can be characterized by quantum process tomography, a complex task that consumes a number of physical resources scaling exponentially with the number of subsystems. An alternative approach to the…

The comprehension of quantum phase transitions (QPTs) is considered as a critical foothold in the field of many-body physics. Developing protocols to effectively identify and understand QPTs thus represents a key but challenging task for…

Quantum Physics · Physics 2025-04-03 Xiangbei Li , Yaoming Chu , Shaoliang Zhang , Jianming Cai

A class of pseudo-hermitian quantum system with an explicit form of the positive-definite metric in the Hilbert space is presented. The general method involves a realization of the basic canonical commutation relations defining the quantum…

Quantum Physics · Physics 2010-03-15 Pijush K. Ghosh

Two-mode interferometers, such as Michelson interferometer based on two spatial optical modes, lay the foundations for quantum metrology. Instead of exploring quantum entanglement in the two-mode interferometers, a single bosonic mode also…

Quantum Physics · Physics 2019-10-14 W. Wang , Y. Wu , Y. Ma , W. Cai , L. Hu , X. Mu , Y. Xu , Zi-Jie Chen , H. Wang , Y. P. Song , H. Yuan , C. -L. Zou , L. -M. Duan , L. Sun

Critical quantum metrology exploits the hypersensitivity of quantum systems near phase transitions to achieve enhanced precision in parameter estimation. While single-parameter estimation near critical points is well established, the…

Quantum Physics · Physics 2026-04-08 Luca Previdi , Yilun Xu , Qiongyi He , Matteo G. A. Paris

Substantial progress has recently been reported in the determination of the Hilbert-Schmidt (HS) separability probabilities for two-qubit and qubit-qutrit (real, complex and quaternionic) systems. An important theoretical concept employed…

Quantum Physics · Physics 2010-06-14 Paul B. Slater

Quantum speed limits (QSLs) provide an upper bound for the speed of evolution of quantum states in any physical process. Based on the Stratonovich-Weyl correspondence, we derive a universal QSL bound in arbitrary phase spaces that is…

Quantum Physics · Physics 2023-08-25 Weiquan Meng , Zhenyu Xu

Preparing the thermal density matrix $\rho_{\beta} \propto e^{-\beta H}$ corresponding to a given Hamiltonian $H$ is a task of central interest across quantum many-body physics, and is particularly salient when attempting to study it with…

Quantum Physics · Physics 2026-01-14 Dominik Hahn , S. A. Parameswaran , Benedikt Placke

A scalable and resource-efficient quantum reinforcement learning framework is presented that eliminates the linear qubit-scaling barrier in multi-step quantum Markov decision processes (QMDPs). The proposed framework integrates a QMDP…

Quantum Physics · Physics 2026-04-23 Thet Htar Su , Shaswot Shresthamali , Masaaki Kondo

Simulating quantum many-body systems (QMBS) is one of the long-standing, highly non-trivial challenges in condensed matter physics and quantum information due to the exponentially growing size of the system's Hilbert space. To date, tensor…

Quantum Physics · Physics 2026-02-06 Belal Abouraya , Jirawat Saiphet , Fedor Jelezko , Ressa S. Said

High fidelity models, which support accurate device characterization and correctly account for environmental effects, are crucial to the engineering of scalable quantum technologies. As it ensures positivity of the density matrix, one…

Quantum Physics · Physics 2017-11-01 S. N. A. Duffus , V. M. Dwyer , M. J. Everitt

We propose a natural application of Quantum Linear Systems Problem (QLSP) solvers such as the HHL algorithm to efficiently prepare highly excited interior eigenstates of physical Hamiltonians in a variational and targeted manner. This is…

Quantum Physics · Physics 2023-10-13 Shao-Hen Chiew , Leong-Chuan Kwek