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We present efficient quantum algorithms for simulating time-dependent Hamiltonian evolution of general input states using an oracular model of a quantum computer. Our algorithms use either constant or adaptively chosen time steps and are…

Quantum Physics · Physics 2011-11-03 Nathan Wiebe , Dominic W. Berry , Peter Hoyer , Barry C. Sanders

In this note we address the exact solutions of a time-dependent Hamiltonian composed by an oscillator-like interaction with both a frequency and a mass term that depend on time. The latter is achieved by constructing the appropriate point…

Quantum Physics · Physics 2020-02-26 Kevin Zelaya , Véronique Hussin

The nature of randomness and complexity growth in systems governed by unitary dynamics is a fundamental question in quantum many-body physics. This problem has motivated the study of models such as local random circuits and their…

Quantum Physics · Physics 2025-10-10 Laura Cui , Thomas Schuster , Liang Mao , Hsin-Yuan Huang , Fernando Brandao

We study classical Hamiltonian systems in which the intrinsic proper time evolution parameter is related through a probability distribution to the physical time, which is assumed to be discrete. - This is motivated by the ``timeless''…

General Relativity and Quantum Cosmology · Physics 2015-06-25 H. -T. Elze

We present a quantum algorithm for simulating the time evolution generated by any bounded, time-dependent operator $-A$ with non-positive logarithmic norm, thereby serving as a natural generalization of the Hamiltonian simulation problem.…

Quantum Physics · Physics 2025-09-15 Guang Hao Low , Rolando D. Somma

It is shown that the standard formulation of quantum mechanics in terms of Hermitian Hamiltonians is overly restrictive. A consistent physical theory of quantum mechanics can be built on a complex Hamiltonian that is not Hermitian but…

Quantum Physics · Physics 2008-12-18 Carl M. Bender , Dorje C. Brody , Hugh F. Jones

A consistent physical theory of quantum mechanics can be built on a complex Hamiltonian that is not Hermitian but instead satisfies the physical condition of space-time reflection symmetry (PT symmetry). Thus, there are infinitely many new…

High Energy Physics - Theory · Physics 2009-11-10 Carl M. Bender , Dorje C. Brody , Hugh F. Jones

In this series of works, we study exactly solvable non-unitary time evolutions in one-dimensional quantum critical systems ranging from quantum quenches to time-dependent drivings. In this part I, we are motivated by the recent works of…

Statistical Mechanics · Physics 2024-10-30 Xueda Wen

The sensitivity of the evolution of quantum uncertainties to the choice of the initial conditions is shown via a complex nonlinear Riccati equation leading to a reformulation of quantum dynamics. This sensitivity is demonstrated for systems…

Quantum Physics · Physics 2015-05-27 Hans Cruz , Dieter Schuch , Octavio Castaños , Oscar Rosas-Ortiz

The controls enacting logical operations on quantum systems are described by time-dependent Hamiltonians that often include rapid oscillations. In order to accurately capture the resulting time dynamics in numerical simulations, a very…

Quantum Physics · Physics 2021-09-29 Ross Shillito , Jonathan A. Gross , Agustin Di Paolo , Élie Genois , Alexandre Blais

In the framework of quasi-Hermitian quantum mechanics it is shown that a weakening of the isotropy of the Hilbert-space geometry can help us to enlarge the domain of the parameters at which the evolution is unitary. The idea is tested using…

Quantum Physics · Physics 2024-08-15 Miloslav Znojil

Current studies about the continuous-variable systems in non-Hermitian quantum mechanics heavily revolved around the singularities in the eigenspectrum by mimicking their discrete-variable counterparts. Discussions over the nonunitary…

Quantum Physics · Physics 2026-04-28 Zhu-yao Jin , Jun Jing

A possible method to investigate non-Hermitian Hamiltonians is suggested through finding a Hermitian operator $\eta_+$ and defining the annihilation and creation operators to be $\eta_+$-pseudo-Hermitian adjoint to each other. The operator…

Quantum Physics · Physics 2014-06-06 Jun-Qing Li , Yan-Gang Miao , Zhao Xue

Update: A time-independent $n\times n$ PT-symmetric (and symmetric) Hamiltonian is diagonalizable since it has all distinct real eigenvalues and the resulting diagonal matrix is a real symmetric matrix. The diagonalization results an…

Quantum Physics · Physics 2014-05-20 Sungwook Lee , Lawrence R. Mead

The proof of the Khalfin Theorem for neutral meson complex is analyzed. It is shown that the unitarity of the time evolution operator for the total system under considerations assures that the Khalfin's Theorem holds. The consequences of…

High Energy Physics - Phenomenology · Physics 2007-12-09 K. Urbanowski , J. Jankiewicz;

The observation of genuine quantum effects in systems governed by non-Hermitian Hamiltonians has been an outstanding challenge in the field. Here we simulate the evolution under such Hamiltonians in the quantum regime on a superconducting…

Quantum Physics · Physics 2021-11-24 Shruti Dogra , Artem A. Melnikov , Gheorghe Sorin Paraoanu

We show that the complex projections of time-dependent $\eta $-quasianti-Hermitian quaternionic Hamiltonian dynamics are complex stochastic dynamics in the space of complex quasi-Hermitian density matrices if and only if a quasistationarity…

Quantum Physics · Physics 2009-11-13 G. Scolarici , L. Solombrino

The issue of separating Schr\"odinger-type quantum time evolution into a product of holonomic and dynamical parts in the non-adiabatic non-Abelian case is examined. We identify all special cases in which this kind of separation is possible,…

Quantum Physics · Physics 2026-02-24 Adam Fredriksson , Erik Sjöqvist

Non-commutativity is one of the most elementary non-classical features of quantum observables. Here we propose a method to detect non-commutativity of interaction Hamiltonians of two probe objects coupled via a mediator. If these objects…

Quantum Physics · Physics 2018-11-20 Tanjung Krisnanda , Ray Ganardi , Su-Yong Lee , Jaewan Kim , Tomasz Paterek

We explore the relation between quantum geometry in non-Hermitian systems and physically measurable phenomena. We highlight various situations in which the behavior of a non-Hermitian system is best understood in terms of quantum geometry,…

Quantum Physics · Physics 2026-03-16 Anton Montag , Tomoki Ozawa