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We provide a brief discussion regarding relativistic limits on the discretization and temporal resolution of time values in a quantum clock. Our clock is characterized by a time observable chosen to be the complement of a bounded and…

Quantum Physics · Physics 2025-10-16 Tommaso Favalli

In this paper we introduce a generalization to the algebraic Bender-Wu recursion relation for the eigenvalues and the eigenfunctions of the anharmonic oscillator. We extend this well known formalism to the time-dependent quantum statistical…

Quantum Physics · Physics 2009-11-07 Florian Weissbach , Axel Pelster , Bodo Hamprecht

We propose a new method for simulating certain type of time-dependent Hamiltonian $H(t) = \sum_{i=1}^m \gamma_i(t) H_i$ where $\gamma_i(t)$ (and its higher order derivatives) is bounded, computable function of time $t$, and each $H_i$ is…

Quantum Physics · Physics 2024-10-21 Nhat A. Nghiem

The self-consistent procedure in electronic structure calculations is revisited using a highly efficient and robust algorithm for solving the non-linear eigenvector problem i.e. H({{\psi}}){\psi} = E{\psi}. This new scheme is derived from a…

Computational Physics · Physics 2015-06-12 Brendan Gavin , Eric Polizzi

In this paper we obtain approximate bound state solutions of $N$-dimensional fractional time independent Schr\"{o}dinger equation for generalised Mie-type potential, namely $V(r^{\alpha})=\frac{A}{r^{2\alpha}}+\frac{B}{r^{\alpha}}+C$. Here…

Mathematical Physics · Physics 2018-03-14 Tapas Das , Uttam Ghosh , Susmita Sarkar , Shantanu Das

We consider the solution of large-scale nonlinear algebraic Hermitian eigenproblems of the form $T(\lambda)v=0$ that admit a variational characterization of eigenvalues. These problems arise in a variety of applications and are…

Numerical Analysis · Mathematics 2015-04-14 Daniel B. Szyld , Eugene Vecharynski , Fei Xue

In this paper, we present a method for the Hamiltonian simulation in the context of eigenvalue estimation problems which improves earlier results dealing with Hamiltonian simulation through the truncated Taylor series. In particular, we…

Quantum Physics · Physics 2018-11-01 Ammar Daskin , Sabre Kais

We present a time-dependent extension of logarithmic perturbation theory for nonrelativistic quantum dynamics governed by the Schr\"odinger equation, in which the logarithm of the wave function is expanded in powers of a coupling constant.…

Quantum Physics · Physics 2026-04-17 Juan Carlos del Valle , Paul Bergold , Karolina Kropielnicka

The real- and imaginary-time evolution of quantum states are powerful tools in physics, chemistry, and beyond, to investigate quantum dynamics, prepare ground states or calculate thermodynamic observables. On near-term devices, variational…

Quantum Physics · Physics 2024-02-27 Julien Gacon , Jannes Nys , Riccardo Rossi , Stefan Woerner , Giuseppe Carleo

We propose an algorithm based on variational quantum imaginary time evolution for solving the Feynman-Kac partial differential equation resulting from a multidimensional system of stochastic differential equations. We utilize the…

Quartic eigenvalue problem $(\lambda^4 A + \lambda^3 B + \lambda^2C + \lambda D + E)x = \mathbf{0}$ naturally arises e.g. when solving the Orr-Sommerfeld equation in the analysis of the stability of the {Poiseuille} flow, in theoretical…

Numerical Analysis · Mathematics 2021-03-10 Zlatko Drmač , Ivana Šain Glibić

Variational quantum eigensolver~(VQE) typically optimizes variational parameters in a quantum circuit to prepare eigenstates for a quantum system. Its applications to many problems may involve a group of Hamiltonians, e.g., Hamiltonian of a…

Quantum Physics · Physics 2021-01-19 Zhan-Hao Yuan , Tao Yin , Dan-Bo Zhang

In our model of quantum gravity the quantum development of a Cauchy hypersurface is governed by a wave equation derived as the result of a canonical quantization process. To find physically interesting solutions of the wave equation we…

Mathematical Physics · Physics 2017-01-23 Claus Gerhardt

The unitary operators U(t), describing the quantum time evolution of systems with a time-dependent Hamiltonian, can be constructed in an explicit manner using the method of time-dependent invariants. We clarify the role of Lie-algebraic…

Mathematical Physics · Physics 2008-05-30 Maciej Kuna , Jan Naudts

A matrix inverse free method to solve time-dependent Schrodinger equation is presented. The method is not subject to form of Hamiltonian and adopting real space grid system such as structured and unstructured grid, and achieves the order N…

Computational Physics · Physics 2007-05-23 Katsuhiro Watanabe , Akihito Kikuchi

In this paper, we derive new relative perturbation bounds for eigenvectors and eigenvalues for regular quadratic eigenvalue problems of the form $\lambda^2 M x + \lambda C x + K x = 0$, where $M$ and $K$ are nonsingular Hermitian matrices…

Numerical Analysis · Mathematics 2021-04-02 Peter Benner , Xin Liang , Suzana Miodragović , Ninoslav Truhar

In a remarkable development Bender and coworkers have shown that it is possible to formulate quantum mechanics consistently even if the Hamiltonian and other observables are not Hermitian. Their formulation, dubbed PT quantum mechanics,…

High Energy Physics - Theory · Physics 2010-11-02 Katherine Jones-Smith , Harsh Mathur

A method based off of operator consideration for solving the time evolution of a wave function is developed. The method is applied to free space, constant force and harmonic oscillator potentials where general solutions are derived for the…

Quantum Physics · Physics 2012-08-14 K. P. Michnicki

In this work, we present a quantum neighborhood preserving embedding and a quantum local discriminant embedding for dimensionality reduction and classification. We demonstrate that these two algorithms have an exponential speedup over their…

Quantum Physics · Physics 2020-03-23 Jin-Min Liang , Shu-Qian Shen , Ming Li , Lei Li

The paper deals with the one-dimensional parabolic potential barrier $V(x)={V_0-m\gamma^2 x^2/2}$, as a model of an unstable system in quantum mechanics. The time-independent Schr\"{o}dinger equation for this model is set up as the…

Mathematical Physics · Physics 2007-05-23 Toshiki Shimbori , Tsunehiro Kobayashi