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Evolutions of local Hamiltonians in short times are expected to remain local and thus limited. In this paper, we validate this intuition by proving some limitations on short-time evolutions of local time-dependent Hamiltonians. We show that…

Quantum Physics · Physics 2022-06-29 Ali Hamed Moosavian , Seyed Sajad Kahani , Salman Beigi

In this paper, we are interested in the minimal null control time of one-dimensional first-order linear hyperbolic systems by one-sided boundary controls. Our main result is an explicit characterization of the smallest and largest values…

Optimization and Control · Mathematics 2021-09-20 Long Hu , Guillaume Olive

In this thesis, we provide an initial investigation into bounds for topological entropy of switched linear systems. Entropy measures, roughly, the information needed to describe the behavior of a system with finite precision on finite time…

Optimization and Control · Mathematics 2016-10-14 James Schmidt

Phenomenological studies of quantum gravity have proposed a modification of the commutator between position and momentum in quantum mechanics so to introduce a minimal uncertainty in position in quantum mechanics. Such a minimal uncertainty…

General Relativity and Quantum Cosmology · Physics 2023-02-10 Pasquale Bosso

A quantum clock must satisfy two basic constraints. The first is a bound on the time resolution of the clock given by the difference between its maximum and minimum energy eigenvalues. The second follows from Holevo's bound on how much…

Quantum Physics · Physics 2009-10-31 V. Buzek , R. Derka , S. Massar

Quantum state control is a fundamental tool for quantum technologies. In this work, we propose and analyze the use of quantum optimal control to exploit the dipolar interaction of ultracold atoms on a lattice ring, focusing on the…

We provide, in an extremely simple way, an upper bound to the minimum number of unitary operators describing a general random-unitary channel.

Quantum Physics · Physics 2007-05-23 Francesco Buscemi

Time-dependent light-matter interactions are a widespread means by which to describe controllable experimental operations. They can be viewed as an approximation in which a third system - the control system - is treated as external within…

Quantum Physics · Physics 2021-02-11 Adam Stokes , Ahsan Nazir

We propose an optimization strategy to control the dynamics of a stochastic system transferred from one thermal equilibrium to another and apply it experimentally to a Brownian particle in an optical trap under compression. Based on a…

It is well known in quantum mechanics that a large energy gap between a Hilbert subspace of specific interest and the remainder of the spectrum can suppress transitions from the quantum states inside the subspace to those outside due to…

Quantum Physics · Physics 2020-05-29 Zongping Gong , Nobuyuki Yoshioka , Naoyuki Shibata , Ryusuke Hamazaki

We show how to implement quantum computation on a system with an intrinsic Hamiltonian by controlling a limited subset of spins. Our primary result is an efficient control sequence on a nearest-neighbor XY spin chain through control of a…

Quantum Physics · Physics 2010-01-27 Alastair Kay , Peter J. Pemberton-Ross

A remarkably simple result is derived for the minimal time $T_{\rm min}$ required to drive a general initial state to a final target state by a Landau-Zener type Hamiltonian or, equivalently, by time-dependent laser driving. The associated…

Quantum Physics · Physics 2015-06-16 Gerhard C. Hegerfeldt

To admit a canonically conjugate time operator, the Hamiltonian has to be a generator of translations (like the momentum operator generates translations in space), so its spectrum must be unbounded. But the Hamiltonian governing our world…

Quantum Physics · Physics 2024-09-02 Ovidiu Cristinel Stoica

Non-classical features of quantum systems can degrade when subjected to environment and noise. Here, we ask a fundamental question: What is the minimum amount of time it takes for a quantum system to exhibit non-classical features in the…

Quantum Physics · Physics 2024-09-23 Divyansh Shrimali , Swapnil Bhowmick , Arun Kumar Pati

Non-unitary operations generated by an effective non-Hermitian Hamiltonian can be used to create quantum state manipulations which are impossible in Hermitian quantum mechanics. These operations include state preparation (or cooling) and…

Quantum Physics · Physics 2014-04-25 Raam Uzdin

For diffusion processes in dimension $d>1$, the statistics of trajectory observables over the time-window $[0,T]$ can be studied via the Feynman-Kac deformations of the Fokker-Planck generator, that can be interpreted as euclidean…

Statistical Mechanics · Physics 2024-01-22 Cecile Monthus

Precision control of a quantum system requires accurate determination of the effective system Hamiltonian. We develop a method for estimating the Hamiltonian parameters for some unknown two-state system and providing uncertainty bounds on…

A quantum system subject to external fields is said to be controllable if these fields can be adjusted to guide the state vector to a desired destination in the state space of the system. Fundamental results on controllability are reviewed…

Nuclear Theory · Physics 2008-11-26 John W. Clark , Dennis G. Lucarelli , Tzyh-Jong Tarn

The reliable and precise generation of quantum unitary transformations is essential to the realization of a number of fundamental objectives, such as quantum control and quantum information processing. Prior work has explored the optimal…

Quantum Physics · Physics 2010-07-21 Michael Hsieh , Rebing Wu , Herschel Rabitz , Daniel Lidar

A modification of the canonical quantization procedure for systems with time-dependent second-class constraints is discussed and applied to the quantization of the relativistic particle in a plane wave. The time dependence of constraints…

High Energy Physics - Theory · Physics 2010-04-06 S. P. Gavrilov , D. M. Gitman