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This paper discusses the quantum mechanics of closed timelike curves (CTC) and of other potential methods for time travel. We analyze a specific proposal for such quantum time travel, the quantum description of CTCs based on post-selected…

Quantum Physics · Physics 2011-07-15 Seth Lloyd , Lorenzo Maccone , Raul Garcia-Patron , Vittorio Giovannetti , Yutaka Shikano

We present a new scheme for the compression of one-way quantum messages, in the setting of coherent entanglement assisted quantum communication. For this, we present a new technical tool that we call the convex split lemma, which is…

Quantum Physics · Physics 2017-09-27 Anurag Anshu , Vamsi Krishna Devabathini , Rahul Jain

Designing quantum algorithms for simulating quantum systems has seen enormous progress, yet few studies have been done to develop quantum algorithms for open quantum dynamics despite its importance in modeling the system-environment…

Quantum Physics · Physics 2022-02-11 Zixuan Hu , Rongxin Xia , Sabre Kais

We present a framework wherein the trajectory optimization problem (or a problem involving calculus of variations) is formulated as a search problem in a discrete space. A distinctive feature of our work is the treatment of discretization…

Optimization and Control · Mathematics 2022-12-22 Alok Shukla , Prakash Vedula

Quantum time evolution exhibits rich physics, attributable to the interplay between the density and phase of a wave function. However, unlike classical heat diffusion, the wave nature of quantum mechanics has not yet been extensively…

Quantum Physics · Physics 2018-08-08 Chenchao Zhao , Jun S. Song

We introduce a novel hybrid algorithm to simulate the real-time evolution of quantum systems using parameterized quantum circuits. The method, named "projected - Variational Quantum Dynamics" (p-VQD) realizes an iterative, global projection…

Quantum Physics · Physics 2021-07-28 Stefano Barison , Filippo Vicentini , Giuseppe Carleo

We show constructively that, under certain regularity assumptions, any system of coupled linear differential equations with variable coefficients can be tridiagonalized by a time-dependent Lanczos-like method. The proof we present formally…

Classical Analysis and ODEs · Mathematics 2021-04-22 P. -L. Giscard , S. Pozza

The simulation of time evolution of large quantum systems is a classically challenging and in general intractable task, making it a promising application for quantum computation. A Trotter-Suzuki approximation yields an implementation…

Evolution in imaginary time is a prominent technique for finding the ground state of quantum many-body systems, and the heart of a number of numerical methods that have been used with great success in quantum chemistry, condensed matter and…

Simulating charge and energy transfer in extended molecular networks requires an effective model to include the environment because it significantly affects the quantum dynamics. A prototypical effect known as Environment-Assisted Quantum…

Quantum Physics · Physics 2022-02-04 Federico Gallina , Matteo Bruschi , Barbara Fresch

We present a quantum algorithm for the dynamical simulation of time-dependent Hamiltonians. Our method involves expanding the interaction-picture Hamiltonian as a sum of generalized permutations, which leads to an integral-free Dyson series…

Quantum Physics · Physics 2021-09-15 Yi-Hsiang Chen , Amir Kalev , Itay Hen

Efficient control of qubits plays a key role in quantum information processing. In the current work, an alternative set of differential equations are derived for an optimal quantum control of single or multiple qubits with or without…

Quantum Physics · Physics 2020-11-26 Ding Wang , Haowei Shi , Yueheng Lan

This work introduces a time-adaptive strategy that uses a refinement estimator based on the first Frenet curvature. In dynamics, a time-adaptive strategy is a mechanism that interactively proposes changes to the time step used in iterative…

Numerical Analysis · Computer Science 2013-05-30 E. N. Lages , E. S. S. Silveira , D. T. Cintra , A. C. Frery

This study introduces time-windowed variations of three established trajectory simplification algorithms. These new algorithms are specifically designed to be used in contexts with bandwidth limitations. We present the details of these…

Other Computer Science · Computer Science 2025-04-10 Gilles Dejaegere , Mahmoud Sakr

Transport and scattering phenomena in open quantum-systems with a continuous energy spectrum are conveniently solved using the time-dependent Schrodinger equation. In the time-dependent picture, the evolution of an initially localized…

Quantum Physics · Physics 2011-05-13 Tobias Kramer

We show that the time evolution operator of kicked quantum systems, although a full matrix of size NxN, can be diagonalized with the help of a new method based on a suitable combination of fast Fourier transform and Lanczos algorithm in…

Condensed Matter · Physics 2009-10-30 R. Ketzmerick , K. Kruse , T. Geisel

The optimal control problem for open quantum systems can be formulated as a time-dependent Lindbladian that is parameterized by a number of time-dependent control variables. Given an observable and an initial state, the goal is to tune the…

Quantum Physics · Physics 2024-05-30 Wenhao He , Tongyang Li , Xiantao Li , Zecheng Li , Chunhao Wang , Ke Wang

We present an alternative temporal approach for convolution, providing a new algorithm, called the taches-algorithm. Based on interferences between the successive delayed and amplified output signals associated respectively with the…

Signal Processing · Electrical Eng. & Systems 2024-01-04 Laurent Millot , Gérard Pelé

The time evolution operator plays a crucial role in the precise computation of chemical experiments on quantum computers and holds immense promise for advancing the fields of physical and computer sciences, with applications spanning…

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