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We consider the problem of controlling in minimum time a two-level quantum system which can be subject to a drift. The control is assumed to be bounded in magnitude, and to affect two or three independent generators of the dynamics. We…

Quantum Physics · Physics 2015-10-28 Raffaele Romano

We derive a Geometric quantum speed limit (QSL) for imaginary-time evolution, where the dynamics is governed by a non-unitary Schr\"{o}dinger equation. By introducing a cost function based on the angular distance between the normalized…

Quantum Physics · Physics 2025-08-15 Kohei Kobayashi

We propose Quantum Riemannian Hamiltonian Descent (QRHD), a quantum algorithm for continuous optimization on Riemannian manifolds that extends Quantum Hamiltonian Descent (QHD) by incorporating geometric structure of the parameter space via…

Quantum Physics · Physics 2026-03-31 Yoshihiko Abe , Ryo Nagai

A fundamental problem in quantum engineering is determining the lowest time required to ensure that all possible unitaries can be generated with the tools available, which is one of a number of possible quantum speed limits. We examine this…

Quantum Physics · Physics 2023-11-03 Mattias T. Johnsson , Lauritz van Luijk , Daniel Burgarth

The dynamics of a closed quantum system is often studied with the direct evolution of the Schrodinger equation. In this paper, we propose that the gauge choice (i.e. degrees of freedom irrelevant to physical observables) of the Schrodinger…

Numerical Analysis · Mathematics 2020-02-20 Dong An , Lin Lin

We discuss the issue of maximal regularity for evolutionary equations with non-autonomous coefficients. Here evolutionary equations are abstract partial-differential algebraic equations considered in Hilbert spaces. The catch is to consider…

Analysis of PDEs · Mathematics 2020-07-01 Sascha Trostorff , Marcus Waurick

We present a unifying variational calculus derivation of Groverian geodesics for both quantum state vectors and quantum probability amplitudes. In the first case, we show that horizontal affinely parametrized geodesic paths on the Hilbert…

Mathematical Physics · Physics 2020-11-16 Carlo Cafaro , Domenico Felice , Paul M. Alsing

We consider how different choices of kinetic energy in Hamiltonian Monte Carlo affect algorithm performance. To this end, we introduce two quantities which can be easily evaluated, the composite gradient and the implicit noise. Results are…

Computation · Statistics 2018-11-19 Samuel Livingstone , Michael F. Faulkner , Gareth O. Roberts

It is known that mixed quantum states are highly entropic states of imperfect knowledge (i.e., incomplete information) about a quantum system, while pure quantum states are states of perfect knowledge (i.e., complete information) with…

Quantum Physics · Physics 2022-11-23 Carlo Cafaro , Paul M. Alsing

Big Data is characterized by Volume, Velocity, Veracity and Complexity. The interaction between this huge data is complex with an associated free will having dynamic and non linear nature. We reduced big data based on its characteristics,…

Other Computer Science · Computer Science 2018-05-30 Sahil Imtiyaz

This work concerns a study of the quantum mechanical extension of the work of Horwitz et al. [1] on the stability of classical Hamiltonian systems by geometrical methods. Simulations are carried out for several important examples, these…

Quantum Physics · Physics 2017-04-12 Gil Elgressy , Lawrence Horwitz

Many optimally scaling quantum simulation algorithms employ controlled time evolution of the Hamiltonian, which is typically the major bottleneck for their efficient implementation. This work establishes a compression protocol for encoding…

Quantum Physics · Physics 2026-04-09 Erenay Karacan

In this paper, we derive sharp lower bounds, also known as quantum speed limits, for the time it takes to transform a quantum system into a state such that an observable assumes its lowest average value. We assume that the system is…

Quantum Physics · Physics 2021-06-02 Dan Allan , Niklas Hörnedal , Ole Andersson

One often needs to estimate how fast an evolving state of a quantum system can depart from some target state or target subspace of a Hilbert space. Such estimates are known as quantum speed limits. We derive a quantum speed limit for a…

Quantum Physics · Physics 2021-08-04 N. Il`in , O. Lychkovskiy

High-dimensional portfolio optimization faces significant computational challenges under complex constraints, with traditional optimization methods struggling to balance convergence speed and global exploration capability. To address this,…

Neural and Evolutionary Computing · Computer Science 2026-04-06 Mingyang Yu , Jiaqi Zhang , Haorui Yang , Adam Slowik , Jun Zhang , Jing Xu

Recently, Bender et al. have considered the quantum brachistochrone problem for the non-Hermitian $\cal PT$-symmetric quantum system and have shown that the optimal time evolution required to transform a given initial state $|\psi_i\rangle$…

Quantum Physics · Physics 2009-07-07 Alexander I. Nesterov

Quantum coherence inherently affects the dynamics and the performances of a quantum machine. Coherent control can, at least in principle, enhance the work extraction and boost the velocity of evolution in an open quantum system. Using…

Quantum Physics · Physics 2018-12-10 Vasco Cavina , Andrea Mari , Alberto Carlini , Vittorio Giovannetti

Shortcuts to adiabaticity provide a general approach to mimic adiabatic quantum processes via arbitrarily fast evolutions in Hilbert space. For these counter-diabatic evolutions, higher speed comes at higher energy cost. Here, the…

Quantum Physics · Physics 2017-12-19 Alan C. Santos , Marcelo S. Sarandy

It is expected that a quantum theory of gravity will radically alter our current notion of spacetime geometry. However, contrary to what was commonly assumed for many decades, quantum gravity effects could manifest in scales much larger…

General Relativity and Quantum Cosmology · Physics 2026-05-14 Eduardo A. B. Oliveira , Andre G. S. Landulfo

We study quantum brachistochrone problem for the spin-1 system in a magnetic field of a constant absolute value. Such system gives us a possibility to examine in detail the statement of papers [A. Carlini {\it et al.}, Phys. Rev. Lett. {\bf…

Quantum Physics · Physics 2009-11-13 A. M. Frydryszak , V. M. Tkachuk
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