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We propose an efficient quantum algorithm for simulating the dynamics of general Hamiltonian systems. Our technique is based on a power series expansion of the time-evolution operator in its off-diagonal terms. The expansion decouples the…

Quantum Physics · Physics 2021-06-22 Amir Kalev , Itay Hen

Quantum systems governed by time-dependent Hamiltonians pose significant challenges for the accurate computation of unitary time-evolution operators, which are essential for predicting quantum state dynamics. In this work, we introduce a…

Quantum Physics · Physics 2026-01-21 Antonio Guerra , Daniel Uzcategui-Contreras , Aldo Delgado , Esteban S. Gómez

Upon revisiting the Hamiltonian structure of classical wavefunctions in Koopman-von Neumann theory, this paper addresses the long-standing problem of formulating a dynamical theory of classical-quantum coupling. The proposed model not only…

Mathematical Physics · Physics 2019-09-06 Denys I. Bondar , François Gay-Balmaz , Cesare Tronci

We demonstrate that quantum fluctuations can cause, under certain conditions, the dynamical instability of pure states that can result in their evolution into mixed states. It is shown that the degree and type of such an instability are…

Quantum Physics · Physics 2015-11-19 Konstantin G. Zloshchastiev

Time reversal in quantum or classical systems described by an Hermitian Hamiltonian is a physically allowed process, which requires in principle inverting the sign of the Hamiltonian. Here we consider the problem of time reversal of a…

Quantum Physics · Physics 2017-06-29 Stefano Longhi

Quantum inverse problem is defined as how to determine a local Hamiltonian from a single eigenstate? This question is valid not only in Hermitian system but also in non-Hermitian system. So far, most attempts are limited to Hermitian…

Quantum Physics · Physics 2024-03-01 Yin Tang , W. Zhu

Data-driven prediction in quantum mechanics consists in providing an approximative description of the motion of any particles at any given time, from data that have been previously collected for a certain number of particles under the…

Analysis of PDEs · Mathematics 2023-02-22 Pedro Caro , Alberto Ruiz

We study time evolution of a subsystem's density matrix under unitary evolution, generated by a sufficiently complex, say quantum chaotic, Hamiltonian, modeled by a random matrix. We exactly calculate all coherences, purity and…

Quantum Physics · Physics 2012-03-15 Vinayak , Marko Znidaric

We propose an approach to analytically solve the quantum dynamics of bosonic systems. The method is based on reconstructing the quantum state of the system from the moments of its annihilation operators, dynamics of which is solved in the…

Quantum Physics · Physics 2019-10-16 Akseli Mäkinen , Joni Ikonen , Matti Partanen , Mikko Möttönen

We provide a new perspective on non-Hermitian evolution in quantum mechanics by emphasizing the same method as in the Hermitian quantum evolution. We first give a precise description of the non unitary evolution, and collecting the basic…

Quantum Physics · Physics 2017-07-21 Mustapha Maamache

We propose a method to manipulate, possibly faster than adiabatically, four-level systems with time-dependent couplings and constant energy shifts (detunings in quantum-optical realizations). We inversely engineer the Hamiltonian, in…

Quantum Physics · Physics 2018-01-24 Y. - C. Li , D. Martínez , S. Martínez-Garaot , X. Chen , J. G. Muga

We consider a non-Hermitian Hamiltonian in order to effectively describe a two-level system coupled to a generic dissipative environment. The total Hamiltonian of the model is obtained by adding a general anti-Hermitian part, depending on…

Quantum Physics · Physics 2013-10-25 Alessandro Sergi , Konstantin G. Zloshchastiev

We present a quantum algorithm to achieve higher-order transformations of Hamiltonian dynamics. Namely, the algorithm takes as input a finite number of queries to a black-box seed Hamiltonian dynamics to simulate a desired Hamiltonian. Our…

Quantum Physics · Physics 2024-06-13 Tatsuki Odake , Hlér Kristjánsson , Akihito Soeda , Mio Murao

We describe a simple, efficient method for simulating Hamiltonian dynamics on a quantum computer by approximating the truncated Taylor series of the evolution operator. Our method can simulate the time evolution of a wide variety of…

Quantum Physics · Physics 2015-03-06 Dominic W. Berry , Andrew M. Childs , Richard Cleve , Robin Kothari , Rolando D. Somma

Ever since the formulation of quantum mechanics, there is very little understanding of the process of the collapse of a wavefunction. We have proposed a dynamical model to emulate the measurement postulates of quantum mechanics. We…

Quantum Physics · Physics 2023-08-16 Gurpahul Singh , Ritesh K. Singh , Soumitro Banerjee

We provide a Hilbert space approach to quantum mechanics where space and time are treated on an equal footing. Our approach replaces the standard dependence on an external classical time parameter with a spacetime-symmetric algebraic…

Quantum Physics · Physics 2026-02-10 N. L. Diaz , R. Rossignoli

We discuss the classical and quantum mechanical evolution of systems described by a Hamiltonian that is a function of a solvable one, both classically and quantum mechanically. The case in which the solvable Hamiltonian corresponds to the…

Quantum Physics · Physics 2015-05-13 J. Fernando Barbero G. , Iñaki Garay , Eduardo J. S. Villaseñor

In principle, non-Hermitian quantum equations of motion can be formulated using as a starting point either the Heisenberg's or the Schr\"odinger's picture of quantum dynamics. Here it is shown in both cases how to map the algebra of…

Quantum Physics · Physics 2011-02-07 Alessandro Sergi

For a quantum system governed by a non-Hermitian Hamiltonian, we studied the problem of obtaining an optimum Hamiltonian that generates nonunitary transformations of a given initial state into a certain final state in the smallest time…

Quantum Physics · Physics 2012-11-15 Alexander I Nesterov

Comprehending the dynamical behaviour of quantum systems driven by time-varying Hamiltonians is particularly difficult. Systems with as little as two energy levels are not yet fully understood as the usual methods including diagonalisation…

Quantum Physics · Physics 2020-10-13 Pierre-Louis Giscard , Christian Bonhomme