scholarly journals Magnetic reversal dynamics of a quantum system on a picosecond timescale

2015 ◽  
Vol 6 ◽  
pp. 1946-1956 ◽  
Author(s):  
Nikolay V Klenov ◽  
Alexey V Kuznetsov ◽  
Igor I Soloviev ◽  
Sergey V Bakurskiy ◽  
Olga V Tikhonova

We present our approach for a consistent, fully quantum mechanical description of the magnetization reversal process in natural and artificial atomic systems by means of short magnetic pulses. In terms of the simplest model of a two-level system with a magnetic moment, we analyze the possibility of a fast magnetization reversal on the picosecond timescale induced by oscillating or short unipolar magnetic pulses. We demonstrate the possibility of selective magnetization reversal of a superconducting flux qubit using a single flux quantum-based pulse and suggest a promising, rapid Λ-scheme for resonant implementation of this process. In addition, the magnetization reversal treatment is fulfilled within the framework of the macroscopic theory of the magnetic moment, which allows for the comparison and explanation of the quantum and classical behavior.

2016 ◽  
pp. 4039-4042
Author(s):  
Viliam Malcher

The interpretation problems of quantum theory are considered. In the formalism of quantum theory the possible states of a system are described by a state vector. The state vector, which will be represented as |ψ> in Dirac notation, is the most general form of the quantum mechanical description. The central problem of the interpretation of quantum theory is to explain the physical significance of the |ψ>. In this paper we have shown that one of the best way to make of interpretation of wave function is to take the wave function as an operator.


2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Zbigniew Dutkiewicz

AbstractDrug design is an expensive and time-consuming process. Any method that allows reducing the time the costs of the drug development project can have great practical value for the pharmaceutical industry. In structure-based drug design, affinity prediction methods are of great importance. The majority of methods used to predict binding free energy in protein-ligand complexes use molecular mechanics methods. However, many limitations of these methods in describing interactions exist. An attempt to go beyond these limits is the application of quantum-mechanical description for all or only part of the analyzed system. However, the extensive use of quantum mechanical (QM) approaches in drug discovery is still a demanding challenge. This chapter briefly reviews selected methods used to calculate protein-ligand binding affinity applied in virtual screening (VS), rescoring of docked poses, and lead optimization stage, including QM methods based on molecular simulations.


2020 ◽  
Vol 230 ◽  
pp. 00003 ◽  
Author(s):  
Dario Ferraro ◽  
Michele Campisi ◽  
Gian Marcello Andolina ◽  
Vittorio Pellegrini ◽  
Marco Polini

Recently the possibility to exploit quantum-mechanical effects to increase the performance of energy storage has raised a great interest. It consists of N two-level systems coupled to a single photonic mode in a cavity. We demonstrate the emergence of a quantum advantage in the charging power on this collective model (Dicke Quantum Battery) with respect to the one in which each two-level system is coupled to its own separate cavity mode (Rabi Quantum Battery). Moreover, we discuss the model of a Quantum Supercapacitor. This consists of two chains, one containing electrons and the other one holes, hosted by arrays of double quantum dots. The two chains are in close proximity and embedded in the same photonic cavity, in the same spirit of the Dicke model. We find the phase diagram of this model showing that, when transitioning from the ferro/antiferromagnetic to the superradiant phase, the quantum capacitance of the model is greatly enhanced.


2014 ◽  
Vol 2 (1) ◽  
Author(s):  
Dong Sun

AbstractWe have shown that the Fano interference in the decay channels of a three-level system can lead to considerably different absorption and emission profiles. We found that a coherence can be built up in the ground state doublet, with strength depending on a coupling parameter that arises from the Fano interference. The coherence can in principle lead to breaking of the detail balance between the absorption and emission processes in atomic systems.


2006 ◽  
Vol 106 (9) ◽  
pp. 2129-2144 ◽  
Author(s):  
Luiz Antônio S. Costa ◽  
Trevor W. Hambley ◽  
Willian R. Rocha ◽  
Wagner B. De Almeida ◽  
Hélio F. Dos Santos

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