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We present a quantum algorithm for the dynamical simulation of time-dependent Hamiltonians. Our method involves expanding the interaction-picture Hamiltonian as a sum of generalized permutations, which leads to an integral-free Dyson series…

Quantum Physics · Physics 2021-09-15 Yi-Hsiang Chen , Amir Kalev , Itay Hen

The Hamiltonian constraint remains an elusive object in loop quantum gravity because its action on spinnetworks leads to changes in their corresponding graphs. As a result, calculations in loop quantum gravity are often considered…

General Relativity and Quantum Cosmology · Physics 2025-07-28 Thiago L. M. Guedes , Guillermo A. Mena Marugán , Markus Müller , Francesca Vidotto

Recently Bender, Brody, Jones and Meister found that in the quantum brachistochrone problem the passage time needed for the evolution of certain initial states into specified final states can be made arbitrarily small, when the…

Quantum Physics · Physics 2008-11-26 Paulo E. G. Assis , Andreas Fring

A quantum clock cannot be modeled as a point mass moving along a single geodesic if it is in a state with nonzero position fluctuations. Instead, it is an extended object subject to tidal forces and a superposition of time dilations at…

Quantum Physics · Physics 2025-03-11 Joseph Balsells , Martin Bojowald

We study the time evolution of quantum systems with a time-dependent non-Hermitian Hamiltonian given by a linear combination of SU(1,1) and SU(2) generators.With a time-dependent metric, the pseudo-Hermitian invariant operator is…

Quantum Physics · Physics 2017-05-24 Mustapha Maamache , Oum Kaltoum Djeghiour , Walid Koussa , Naima Mana

We construct a class of fixed-time models in which the commutations relations of a Dirac field with a bosonic field are non-trivial and depend on the choice of a given distribution ("twisting factor"). If the twisting factor is fundamental…

Mathematical Physics · Physics 2024-11-06 Ezio Vasselli

The quantum Fisher information, the quantum analogue of the classical Fisher information, is a central quantity in quantum metrology and quantum sensing due to its connection to parameter estimation and fidelity susceptibility. Using…

We present a second quantization description of frequency-based continuous variables quantum computation in the subspace of single photons. For this, we define frequency and time operators using the free field Hamiltonian and its Fourier…

Quantum Physics · Physics 2022-06-01 Nicolas Fabre , Camille Nous , Arne Keller , Pérola Milman

A quantum-mechanical Hamiltonian with a gravitational potential is derived in the framework of local times. This Hamiltonian is the one used by E. H. Lieb (Bull. Amer. Math. Soc. 22(1990), 1-49) in his explanation of stability and…

General Relativity and Quantum Cosmology · Physics 2008-02-03 Hitoshi Kitada

Recently, Zhong et al. [Phys. Rev. A 87, 022337(2013)] investigated the dynamics of quantum Fisher information (QFI) in the presence of decoherence. We here reform their results and propose two schemes to enhance and preserve the QFIs for a…

Quantum Physics · Physics 2016-10-28 Youneng Guo , Maofa Fang , Gouyou Wang , Jiang Huang , Ke Zeng

In recent proposals for achieving optical super-resolution, variants of the Quantum Fisher Information (QFI) quantify the attainable precision. We find that claims about a strong enhancement of the resolution resulting from coherence…

Quantum Physics · Physics 2019-11-14 Zdeněk Hradil , Jaroslav Řeháček , Luis Sánchez-Soto , Berthold-Georg Englert

A practical way to deal with the problem of time in quantum cosmology and quantum gravity is proposed. The main tool is effective equations, which mainly restrict explicit considerations to semiclassical regimes but have the crucial…

General Relativity and Quantum Cosmology · Physics 2011-07-20 Martin Bojowald , Philipp A Hoehn , Artur Tsobanjan

In this study, considering the Fisher information metric (Fisher metric) given by a specific form, which is the form of weights in statistical physics, we rewrite the Einstein-Hilbert (EH) action. Then, determining the transformation rules…

High Energy Physics - Theory · Physics 2020-09-29 Shingo Takeuchi

The problem of time in the quantization of gravity arises from the fact that time in Schroedinger's equation is a parameter. This sets time apart from the spatial coordinates, represented by operators in quantum mechanics (QM). Thus "time"…

General Relativity and Quantum Cosmology · Physics 2016-05-06 M. Bauer

For a large class of time-dependent non-Hermitain Hamiltonians expressed in terms linear and bilinear combinations of the generators for an Euclidean Lie-algebra respecting different types of PT-symmetries, we find explicit solutions to the…

Quantum Physics · Physics 2019-01-17 Andreas Fring , Thomas Frith

Quantum sensors driven into the quantum chaotic regime can have dramatically enhanced sensitivity, which, however, depends intricately on the details of the underlying classical phase space. Here, we develop an accurate semiclassical…

Quantum Physics · Physics 2026-01-26 Mahdi RouhbakhshNabati , Daniel Braun , Henning Schomerus

Quantum mechanical time operator is introduced following the parametric formulation of classical mechanics in the extended phase space. Quantum constraint on the extended quantum system is defined in analogy to the constraint of the…

Quantum Physics · Physics 2011-02-15 Nikola Buri\' c , Slobodan Prvanovi\' c

We develop a mathematical framework for quantum time transfer based on commuting families of Hamiltonians and synchronization observables. The synchronization subspace is defined as the kernel of a difference operator between local clocks,…

Quantum Physics · Physics 2025-10-09 Nicholas R. Allgood

We investigate the power of quantum systems for the simulation of Hamiltonian time evolutions on a cubic lattice under the constraint of translational invariance. Given a set of translationally invariant local Hamiltonians and short range…

Quantum Physics · Physics 2009-11-13 Christina V. Kraus , Michael M. Wolf , J. Ignacio Cirac

In this paper we study the Fisher information metric on the space of the coupling constants on both sides of the duality between non-relativistic dipole field theories and string theory in Schr\"odinger spacetime. We consider the following…

High Energy Physics - Theory · Physics 2021-10-07 H. Dimov , I. N. Iliev , M. Radomirov , R. C. Rashkov , T. Vetsov
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