scholarly journals The Renewed Role of Sweep Functions in Noisy Shortcuts to Adiabaticity

Entropy ◽  
2021 ◽  
Vol 23 (7) ◽  
pp. 897
Author(s):  
Michele Delvecchio ◽  
Francesco Petiziol ◽  
Sandro Wimberger
Keyword(s):  
Quantum System ◽  
Quantum Systems ◽  
Shortcuts To Adiabaticity ◽  
Experimental Implementation ◽  
Free Case ◽  
Control Of Quantum Systems

We study the robustness of different sweep protocols for accelerated adiabaticity following in the presence of static errors and of dissipative and dephasing phenomena. While in the noise-free case, counterdiabatic driving is, by definition, insensitive to the form of the original sweep function, this property may be lost when the quantum system is open. We indeed observe that, according to the decay and dephasing channels investigated here, the performance of the system becomes highly dependent on the sweep function. Our findings are relevant for the experimental implementation of robust shortcuts-to-adiabaticity techniques for the control of quantum systems.

scholarly journals Más allá de la presuposición newtoniana: propiedades genuinamente disposicionales en la mecánica cuántica

1990 ◽  
Vol 22 (66) ◽  
pp. 25-37
Author(s):  
Sergio Martínez
Keyword(s):  
Quantum Mechanics ◽  
Quantum System ◽  
Physical System ◽  
Modern Science ◽  
Quantum Systems ◽  
Theoretical Modeling ◽  
Different Types ◽  
Modern Physics ◽  
Dispositional Properties

A central metaphysical thesis of modern science has been the idea that the structure of a physical system can be explained in terms of the properties of its constitutive subsystems. I call this presupposition the Newtonian merological presupposition. After some brief introductory remarks on the role of this presupposition in the methodology of modern physics, and after mentioning some recent challenges to it, I focus my attention on quantum systems. Quantum mechanics is the only highly confirmed theory in which the Newtonian merological presupposition is denied. I argue that the presence of a non-Newtonian (holistic) merological structure is the result of the existence of two different types of properties, and in particular of the existence of genuinely dispositional properties. Genuinely dispositional properties are properties of a system which are not reducible to occurrent properties of the subsystems. This distinction between two different types of properties can be made precise in a lattice theoretical modeling of the possible properties and states attributable to a quantum system. I conclude by giving an example of the sort of genuinely dispositional properties that are constitutive of quantum systems.

scholarly journals Thermalization of small quantum systems: From the zeroth law of thermodynamics

2021 ◽  
Author(s):  
Jiaozi Wang ◽  
Wen-Ge Wang ◽  
Jiao Wang
Keyword(s):  
Quantum System ◽  
Chaotic Systems ◽  
Environmental Temperature ◽  
Quantum Systems ◽  
Necessary Condition ◽  
Environmental System ◽  
Small System ◽  
Composite Systems ◽  
Small Quantum

Abstract Thermalization of isolated quantum systems has been studied intensively in recent years and significant progresses have been achieved. Here, we study thermalization of small quantum systems that interact with large chaotic environments under the consideration of Schrödinger evolution of composite systems, from the perspective of the zeroth law of thermodynamics. Namely, we consider a small quantum system that is brought into contact with a large environmental system; after they have relaxed, they are separated and their temperatures are studied. Our question is under what conditions the small system may have a detectable temperature that is identical with the environmental temperature. This should be a necessary condition for the small quantum system to be thermalized and to have a well-defined temperature. By using a two-level probe quantum system that plays the role of a thermometer, we find that the zeroth law is applicable to quantum chaotic systems, but not to integrable systems.

scholarly journals Decoherence and the conditions for the classical control of quantum systems

2012 ◽  
Vol 370 (1975) ◽  
pp. 4469-4486 ◽  
Author(s):  
G. J. Milburn
Keyword(s):  
Quantum System ◽  
Open System ◽  
Stochastic Dynamics ◽  
Quantum Systems ◽  
Mechanical Resonator ◽  
Controlled System ◽  
Control Of Quantum Systems ◽  
Classical Control

We find the conditions for one quantum system to function as a classical controller of another quantum system: the controller must be an open system and rapidly diagonalized in the diagonal basis of the controller variable that is coupled to the controlled system. This causes decoherence in the controlled system that can be made small if the rate of diagonalization is fast. We give a detailed example based on the quantum optomechanical control of a mechanical resonator. The resulting equations are structurally similar to recently proposed models for consistently combining quantum and classical stochastic dynamics.

scholarly journals A Quantum System Control Method Based on Enhanced Reinforcement Learning

2021 ◽  
Author(s):  
Wenjie Liu ◽  
Bosi Wang ◽  
Jihao Fan ◽  
Yebo Ge ◽  
Mohammed Zidan
Keyword(s):  
Reinforcement Learning ◽  
Quantum System ◽  
Control Method ◽  
Quantum Systems ◽  
System Control ◽  
Control Task ◽  
Initial State ◽  
Simulation Experiments ◽  
Switch Control ◽  
Control Of Quantum Systems

Abstract The design of quantum system control is a key task to a powerful quantum information technology. In practical, traditional quantum system control methods often face different constraints, and are easy to cause both leakage and stochastic control errors under the condition of limited resources. Reinforcement learning has been proved as an efficient way to complete the quantum system control task. So a quantum system control method based on enhanced reinforcement learning (QSC-ERL) is proposed. A satisfactory control strategy is obtained through enhanced reinforcement learning so that the quantum system can be evolved accurately from the initial state to the target state. According to the number of candidate unitary operations, the three-switch control is used for simulation experiments. Compared with other methods, the QSC-ERL can achieve high fidelity learning control of quantum systems and improve the efficiency of quantum system control.

scholarly journals Multiparticle quantum plasmonics

Nanophotonics ◽  
2020 ◽  
Vol 9 (6) ◽  
pp. 1243-1269 ◽  
Author(s):  
Chenglong You ◽  
Apurv Chaitanya Nellikka ◽  
Israel De Leon ◽  
Omar S. Magaña-Loaiza
Keyword(s):  
Quantum Dynamics ◽  
Degrees Of Freedom ◽  
Single Photon ◽  
Quantum Systems ◽  
Many Body ◽  
Statistical Fluctuations ◽  
Quantum Plasmonics ◽  
Control Of Quantum Systems ◽  
Multiparticle Systems ◽  
Quantum Photonics

AbstractA single photon can be coupled to collective charge oscillations at the interfaces between metals and dielectrics forming a single surface plasmon. The electromagnetic near-fields induced by single surface plasmons offer new degrees of freedom to perform an exquisite control of complex quantum dynamics. Remarkably, the control of quantum systems represents one of the most significant challenges in the field of quantum photonics. Recently, there has been an enormous interest in using plasmonic systems to control multiphoton dynamics in complex photonic circuits. In this review, we discuss recent advances that unveil novel routes to control multiparticle quantum systems composed of multiple photons and plasmons. We describe important properties that characterize optical multiparticle systems such as their statistical quantum fluctuations and correlations. In this regard, we discuss the role that photon-plasmon interactions play in the manipulation of these fundamental properties for multiparticle systems. We also review recent works that show novel platforms to manipulate many-body light-matter interactions. In this spirit, the foundations that will allow nonexperts to understand new perspectives in multiparticle quantum plasmonics are described. First, we discuss the quantum statistical fluctuations of the electromagnetic field as well as the fundamentals of plasmonics and its quantum properties. This discussion is followed by a brief treatment of the dynamics that characterize complex multiparticle interactions. We apply these ideas to describe quantum interactions in photonic-plasmonic multiparticle quantum systems. We summarize the state-of-the-art in quantum devices that rely on plasmonic interactions. The review is concluded with our perspective on the future applications and challenges in this burgeoning field.

scholarly journals Simulating molecules on a cloud-based 5-qubit IBM-Q universal quantum computer

2021 ◽  
Vol 4 (1) ◽  
Author(s):  
S. Leontica ◽  
F. Tennie ◽  
T. Farrow
Keyword(s):  
Quantum System ◽  
Energy Transport ◽  
Quantum Computer ◽  
Complex Molecule ◽  
Dissipative System ◽  
Quantum Simulation ◽  
Quantum Systems ◽  
Molecular Structures ◽  
Unitary Evolution ◽  
Universal Quantum

AbstractSimulating the behaviour of complex quantum systems is impossible on classical supercomputers due to the exponential scaling of the number of quantum states with the number of particles in the simulated system. Quantum computers aim to break through this limit by using one quantum system to simulate another quantum system. Although in their infancy, they are a promising tool for applied fields seeking to simulate quantum interactions in complex atomic and molecular structures. Here, we show an efficient technique for transpiling the unitary evolution of quantum systems into the language of universal quantum computation using the IBM quantum computer and show that it is a viable tool for compiling near-term quantum simulation algorithms. We develop code that decomposes arbitrary 3-qubit gates and implement it in a quantum simulation first for a linear ordered chain to highlight the generality of the approach, and second, for a complex molecule. We choose the Fenna-Matthews-Olsen (FMO) photosynthetic protein because it has a well characterised Hamiltonian and presents a complex dissipative system coupled to a noisy environment that helps to improve the efficiency of energy transport. The method can be implemented in a broad range of molecular and other simulation settings.

THE TRAPPED-ION QUBIT: COHERENT CONTROL IN INFINITE-DIMENSIONAL QUANTUM SYSTEMS

2009 ◽  
Vol 24 (32) ◽  
pp. 2565-2578
Author(s):  
C. RANGAN
Keyword(s):  
Quantum Computing ◽  
Quantum System ◽  
Quantum Control ◽  
Coherent Control ◽  
Quantum Information Processing ◽  
Quantum Systems ◽  
Infinite Dimensional ◽  
Trapped Ion ◽  
Rich Variety ◽  
Control Research

Theories of quantum control have, until recently, made the assumption that the Hilbert space of a quantum system can be truncated to finite dimensions. Such truncations, which can be achieved for most quantum systems via bandwidth restrictions, have enabled the development of a rich variety of quantum control and optimal control schemes. Recent studies in quantum information processing have addressed the control of infinite-dimensional quantum systems such as the quantum states of a trapped-ion. Controllability in an infinite-dimensional quantum system is hard to prove with conventional methods, and infinite-dimensional systems provide unique challenges in designing control fields. In this paper, we will discuss the control of a popular system for quantum computing the trapped-ion qubit. This system, modeled by a spin-half particle coupled to a quantized harmonic oscillator, is an example for a surprisingly rich variety of control problems. We will show how this infinite-dimensional quantum system can be examined via the lens of the Finite Controllability Theorem, two-color STIRAP, the generalized Heisenberg system, etc. These results are important from the viewpoint of developing more efficient quantum control protocols, particularly in quantum computing systems. This work shows how one can expand the scope of quantum control research to beyond that of finite-dimensional quantum systems.

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