scholarly journals Thermal quantum speed limit for classical-driving open systems

2016 ◽  
Vol 30 (32n33) ◽  
pp. 1650389
Author(s):  
W.-J. Wu ◽  
K. Yan ◽  
Yinzhong Wu ◽  
Xiang Hao
Keyword(s):  
Low Temperature ◽  
Open System ◽  
Open Systems ◽  
Quantum Evolution ◽  
Speed Limit ◽  
Driving Field ◽  
Potential Capacity ◽  
Classical Fields ◽  
Evolution Speed ◽  
Quantum Speedup

Quantum speed limit (QSL) time for open systems driven by classical fields is studied in the presence of thermal bosonic environments. The decoherence process is quantitatively described by the time convolutionless master equation. The evolution speed of an open system can be accelerated by means of driving classical fields at finite temperatures. It is found out that the structural reservoir at low temperature may contribute to the acceleration of quantum evolution. The manifest oscillation of QSL time happens under the circumstance of classical driving field. The scaling property of QSL for entangled systems is also investigated. It is demonstrated that the entanglement of open systems can be considered as one kind of resource for improving the potential capacity of thermal quantum speedup.

Quantum speed limit time of a spin qubit in noninteracting spin bath

2019 ◽  
Vol 17 (07) ◽  
pp. 1950054
Author(s):  
Muhammad Musadiq ◽  
Salman Khan ◽  
Muhammad Javed ◽  
Mahmood Shamirzaie
Keyword(s):  
Approximate Solutions ◽  
Temperature Limit ◽  
Quantum Evolution ◽  
Speed Limit ◽  
Spin Bath ◽  
Driving Time ◽  
Potential Capacity ◽  
Limit Time ◽  
Speed Up ◽  
Spin Qubit

We study the dynamic of quantum speed limit (QSL) time of a qubit coupled to a bath of noninteracting spins. The investigations are carried under both exact and approximate solutions of the model and the results of the two approaches are compared with each other. Under the exact solution and in the low temperature limit, QSL time becomes independent of the number of spins in the environment with potential capacity for quantum speed up. Beyond a critical value of temperature, there exists a frequency of the spins that reduces the capacity for speeding up quantum evolution. The effects of driving time, nonuniform frequencies of the bath’s spins and coupling strength on QSL time are also investigated.

Resolvent limits of the quantum evolution of open systems

2006 ◽  
Vol 80 (3-4) ◽  
pp. 454-458
Author(s):  
G. V. Ryzhakov
Keyword(s):  
Open Systems ◽  
Quantum Evolution

THE QUANTUM TRAJECTORY APPROACH TO GEOMETRIC PHASE FOR OPEN SYSTEMS

2005 ◽  
Vol 20 (22) ◽  
pp. 1635-1654 ◽  
Author(s):  
ANGELO CAROLLO
Keyword(s):  
Quantum System ◽  
Open System ◽  
Geometric Phase ◽  
Open Systems ◽  
Quantum Trajectory ◽  
Operational Method ◽  
Markovian Approximation ◽  
Physical Systems ◽  
Quantum Jump ◽  
Trajectory Approach

The quantum jump method for the calculation of geometric phase is reviewed. This is an operational method to associate a geometric phase to the evolution of a quantum system subjected to decoherence in an open system. The method is general and can be applied to many different physical systems, within the Markovian approximation. As examples, two main source of decoherence are considered: dephasing and spontaneous decay. It is shown that the geometric phase is to very large extent insensitive to the former, i.e. it is independent of the number of jumps determined by the dephasing operator.

Aspects of the weak-coupling theory of open systems

1983 ◽  
Vol 61 (11) ◽  
pp. 1479-1485 ◽  
Author(s):  
I. D. Cox ◽  
W. E. Hagston ◽  
B. J. Holmes
Keyword(s):  
Perturbation Theory ◽  
Open System ◽  
Weak Coupling ◽  
Open Systems ◽  
Higher Order ◽  
Projection Operators ◽  
Coupling Theory ◽  
Weak Coupling Theory ◽  
Damping Theory ◽  
Insight Into

Damping theory of an open system S is usually formulated in terms of projection operators which introduce nonuniqueness into the analysis. An insight into the nature of the approximations that arise from this aspect of the formalism is revealed by considering systems of varying complexity. This leads to the conclusion that the results of higher order perturbation theory approximations may not be meaningful.

scholarly journals Quantum speedup, non-Markovianity and formation of bound state

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Bahram Ahansaz ◽  
Abbas Ektesabi
Keyword(s):  
Bound States ◽  
Decisive Role ◽  
Bound State ◽  
Negative Energy ◽  
Quantum Evolution ◽  
Level System ◽  
System Environment ◽  
Speed Up ◽  
The Relationship ◽  
Quantum Speedup

Abstract In this paper, we investigate the relationship between the quantum speedup, non-Markovianity and formation of a system-environment bound state. Previous results show a monotonic relation between these three such that providing bound states with more negative energy can lead to a higher degree of non-Markovianity, and hence to a greater speed of quantum evolution. By studying dynamics of a dissipative two-level system or a V-type three-level system, when similar and additional systems are present, we reveal that the quantum speedup is exclusively related to the formation of the system-environment bound state, while the non-Markovian effect of the system dynamics is neither necessary nor sufficient to speed up the quantum evolution. On the other hand, it is shown that only the formation of the system-environment bound state plays a decisive role in the acceleration of the quantum evolution.

QUANTIZATION OF NON-LAGRANGIAN SYSTEMS

2009 ◽  
Vol 24 (28n29) ◽  
pp. 5319-5340 ◽  
Author(s):  
DENIS KOCHAN
Keyword(s):  
Variational Principle ◽  
Open Systems ◽  
Transition Probability ◽  
Functional Integral ◽  
Quantum Evolution ◽  
Lagrangian Systems ◽  
Classical Dynamics ◽  
Standard Case ◽  
Calculus Of Variation ◽  
Novel Method

A novel method for quantization of non-Lagrangian (open) systems is proposed. It is argued that the essential object, which provides both classical and quantum evolution, is a certain canonical two-form defined in extended velocity space. In this setting classical dynamics is recovered from the stringy-type variational principle, which employs umbilical surfaces instead of histories of the system. Quantization is then accomplished in accordance with the introduced variational principle. The path integral for the transition probability amplitude (propagator) is rearranged to a surface functional integral. In the standard case of closed (Lagrangian) systems the presented method reduces to the standard Feynman's approach. The inverse problem of the calculus of variation, the problem of quantization ambiguity and the quantum mechanics in the presence of friction are analyzed in detail.

E-Cigarettes: Policy Options and Legal Issues Amidst Uncertainty

2015 ◽  
Vol 43 (S1) ◽  
pp. 23-26 ◽  
Author(s):  
Nancy Kaufman ◽  
Margaret Mahoney
Keyword(s):  
Smoking Cessation ◽  
Propylene Glycol ◽  
Open System ◽  
Closed System ◽  
Open Systems ◽  
Delivery Systems ◽  
Legal Issues ◽  
Policy Options ◽  
Electronic Nicotine Delivery Systems ◽  
Closed Systems

E-cigarettes, sometimes referred to as ENDS (Electronic Nicotine Delivery Systems), include a broad range of products that deliver nicotine via heating and aerosolization of the drug. ENDS come in a variety of forms, but regardless of form generally consist of a solution containing humectant (e.g., propylene glycol or glycerol), flavorings, and usually nicotine (some solutions do not contain nicotine); a battery-powered coil that heats the solution into an aerosol (usually referred to as vapor) in an atomizing chamber; and a mouthpiece through which the user draws the vapor into the mouth and lungs. The devices may be closed systems containing prefilled cartridges, or open systems, where the user manually refills a 1-2 ml. tank with solution. What started as closed-system cigarette-shaped devices marketed as an adjunct for smoking cessation, has transitioned rapidly to literally thousands of hip and funky-designed open-system hookah pens, vape pens, and modifiable devices. For younger people, these forms are the “in” thing, while traditional cigarette-shaped devices are “out.”

scholarly journals Economics and interdisciplinarity: an open-systems approach

2017 ◽  
Vol 37 (2) ◽  
pp. 343-362
Author(s):  
VÍTOR NEVES
Keyword(s):  
Political Economy ◽  
Open System ◽  
Systems Approach ◽  
Open Systems ◽  
Object Of Study

ABSTRACT This is a text on economics and interdisciplinarity. It takes account of the plurality of meanings that the practice of interdisciplinarity has assumed in economics, discusses why interdisciplinarity is essential to the study of the economy and analyzes two models of what interdisciplinarity should be in economics. Reference is also made to the obstacles inherent in the practice of interdisciplinarity. Its ultimate goal is to show why the economy (as an object of study), being an open system, cannot be left to economists alone requiring, instead, a pluralistic, political economy understanding of the ‘economic’.

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