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Related papers: Non-unitary Time Evolution via the Chebyshev Expan…

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In this work, we propose a testing procedure to distinguish between the different approaches for computing complexity. Our test does not require a direct comparison between the approaches and thus avoids the issue of choice of gates, basis,…

High Energy Physics - Theory · Physics 2019-04-15 Tibra Ali , Arpan Bhattacharyya , S. Shajidul Haque , Eugene H. Kim , Nathan Moynihan

The manuscript presents a new technique for computing the exponential of skew-Hermitian operators. Principal advantages of the proposed method include: stability even for large time-steps, the possibility to parallelize in time over many…

Numerical Analysis · Mathematics 2014-02-24 T. S. Haut , T. Babb , P. G. Martinsson , B. A. Wingate

Quantum simulation using time evolution in phase estimation-based quantum algorithms can yield unbiased solutions of classically intractable models. However, long runtimes open such algorithms to decoherence. We show how measurement-based…

Quantum Physics · Physics 2022-08-11 Woo-Ram Lee , Zhangjie Qin , Robert Raussendorf , Eran Sela , V. W. Scarola

Simulating time evolution of generic quantum many-body systems using classical numerical approaches has an exponentially growing cost either with evolution time or with the system size. In this work, we present a polynomially scaling hybrid…

Quantum Physics · Physics 2023-09-18 Nikita Astrakhantsev , Sheng-Hsuan Lin , Frank Pollmann , Adam Smith

We discuss the short-time perturbative expansion of the linear entropy for finite-dimensional quantum systems whose dynamics can be effectively described by a non-Hermitian Hamiltonian. We derive a timescale for the degree of mixedness for…

Quantum Physics · Physics 2023-02-07 Diego Paiva Pires , Tommaso Macrì

We improve a recently developed expansion technique for calculating real frequency spectral functions of any one-dimensional model with short-range interactions, by postprocessing computed Chebyshev moments with linear prediction. This can…

Strongly Correlated Electrons · Physics 2014-08-06 Martin Ganahl , Patrik Thunström , Frank Verstraete , Karsten Held , Hans Gerd Evertz

Engineering quantum bath networks through non-Hermitian subsystem Hamiltonians has recently emerged as a promising strategy for qubit cooling, state stabilization, and fault-tolerant quantum computation. However, scaling these systems while…

We investigated the quantum speed limit time of a qubit system with non-Hermitian detuning. Our results show that, with respect to two distinguishable states of the non-Hermitian system, the evolutionary time does not have a nonzero lower…

Quantum Physics · Physics 2018-10-23 Yan-Yi Wang , Mao-Fa Fang

We apply the Wiener Hermite (WH) expansion to the non-linear evolution of Large-Scale Structure, and obtain an approximate expression for the matter power spectrum in full order of the expansion. This method allows us to expand any random…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-11 Naonori S. Sugiyama , Toshifumi Futamase

Time-independent scattering methods are widely employed to analyze transport in non-Hermitian systems. Their application, however, rests on a critical yet often overlooked assumption: that an incident wave is a pure superposition of…

Quantum Physics · Physics 2025-11-04 Chao Zheng

Exponential divided differences arise in numerical linear algebra, matrix-function evaluation, and quantum Monte Carlo simulations, where they serve as kernel weights for time evolution and observable estimation. Efficient and numerically…

Computational Physics · Physics 2025-12-30 Itay Hen

In optimal quantum-mechanical evolutions, motion can take place along paths of minimal length within an optimal time frame. Alternatively, optimal evolutions may occur along established paths without any waste of energy resources and…

Quantum Physics · Physics 2026-01-16 Carlo Cafaro , James Schneeloch

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

This work discusses Hermitian and non-Hermitian formulations for the time evolution of quantum decay, that involve respectively, continuum wave functions and resonant states, to show that they lead to an identical description for a large…

Quantum Physics · Physics 2013-02-28 Gastón García-Calderón , Alejandro Máttar , Jorge Villavicencio

We explore the applicability of a stochastic time-evolution algorithm based on probabilistic angle interpolation. To simplify the pre-processing of the algorithm, we take the continuous-time limit, thereby explicitly eliminating Trotter…

Quantum Physics · Physics 2026-04-06 Tomoya Hayata , Yuta Kikuchi

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

In the geometry of quantum-mechanical processes, the time-varying curvature coefficient of a quantum evolution is specified by the magnitude squared of the covariant derivative of the tangent vector to the state vector. In particular, the…

Quantum Physics · Physics 2025-01-07 Carlo Cafaro , Leonardo Rossetti , Paul M. Alsing

Simulating time evolution of quantum systems is one of the most promising applications of quantum computing and also appears as a subroutine in many applications such as Green's function methods. In the current era of NISQ machines we…

Quantum Physics · Physics 2021-06-21 Nathan Fitzpatrick , Harriet Apel , David Muñoz Ramo

This work provides a nonasymptotic error analysis of quantum Krylov algorithms based on real-time evolutions, subject to generic errors in the outputs of the quantum circuits. We prove upper and lower bounds on the resulting ground state…

Quantum Physics · Physics 2024-09-04 William Kirby

Hamiltonian simulation is a central task in quantum computing, with wide-ranging applications in quantum chemistry, condensed matter physics, and combinatorial optimization. A fundamental challenge lies in approximating the unitary…

Quantum Physics · Physics 2025-05-15 Molena Nguyen , Naihuan Jing