Classical system underlying a diffracting quantum billiard

Pramana ◽  
2018 ◽  
Vol 90 (2) ◽  
Author(s):  
Manan Jain
2021 ◽  
Vol 182 (3) ◽  
Author(s):  
Christian B. Mendl ◽  
Folkmar Bornemann

AbstractThis work presents an efficient numerical method to evaluate the free energy density and associated thermodynamic quantities of (quasi) one-dimensional classical systems, by combining the transfer operator approach with a numerical discretization of integral kernels using quadrature rules. For analytic kernels, the technique exhibits exponential convergence in the number of quadrature points. As demonstration, we apply the method to a classical particle chain, to the semiclassical nonlinear Schrödinger (NLS) equation and to a classical system on a cylindrical lattice. A comparison with molecular dynamics simulations performed for the NLS model shows very good agreement.


1991 ◽  
Vol 44 (11S) ◽  
pp. S194-S198 ◽  
Author(s):  
Anibal E. Mirasso ◽  
Luis A. Godoy

Critical and postcritical states of pseudo-conservative discrete structural systems are studied by means of a new formulation leading to a classification of critical states and to an approximate form of the postcritical equilibrium path. The nonlinear equilibrium equations are derived from the total potential energy function of a classical system, but with the addition of at least one control parameter. The follower force effect is thus included by nonlinear constraints to the equilibrium equation. The nonlinear equations are solved by perturbation techniques. Finally the theory is applied to investigate the instability of some simple mechanical models.


2002 ◽  
Vol 16 (30) ◽  
pp. 4593-4605 ◽  
Author(s):  
G. GIORGADZE

In this work, a gauge approach to quantum computing is considered. It is assumed that there exists a classical procedure for placing certain classical system in a state described by a holomorphic vector bundle with connection with logarithmic singularities. This bundle and its connection are constructed with the aid of unitary operators realizing the given algorithm using methods of the monodromic Riemann–Hilbert problem. Universality is understood in the sense that for any collection of unitary matrices there exists a connection with logarithmic singularities whose monodromy representation involves these matrices.


2013 ◽  
Vol 22 (02) ◽  
pp. 1330001 ◽  
Author(s):  
YONGJOON KWON ◽  
SOONKEON NAM

From the quasinormal modes (QNM) of black holes, we obtain the quantizations of the entropy and horizon area of black holes via Bohr–Sommerfeld quantization, based on Bohr's correspondence principle. For this, we identify the appropriate action variable of the classical system corresponding to a black hole. By considering the BTZ black holes in topologically massive gravity as well as Einstein gravity, it is found that the spectra of not the horizon areas but the entropies of black holes are equally spaced. We also propose that other characteristic modes of black holes, which are non-QNM or holographic QNM, can be used in quantization of entropy spectra just like QNM. From these modes, it is found that only the entropy spectrum of the warped AdS3 black hole is equally spaced as well. Furthermore, by considering a scattering problem in a black hole, we propose that the total transmission modes and total reflection modes of black holes can be regarded as characteristic modes of black holes and result in the equally spaced entropy of the Kerr and Reissner–Nordström black holes. Finally, we conclude that there is a universal behavior that the entropy spectra of various black holes are equally spaced.


2021 ◽  
Author(s):  
Elnaz Rostampour

Abstract We theoretically express quantum transport at Dirac points via graphene quantum billiard as a non-magnetic material to connect metallic leads. Our results indicate that the quantum billiard of graphene is similar to a resonant tunnelling device. The centerpiece size and the Fermi energy of the graphene quantum billiard play an important role in the resonant tunnelling. In graphene, change of carrier density can affect plasmon polaritons. At the Dirac point, the conductivity of graphene depends on the geometry, so that the conduction of the evanescent modes is close to the theoretical value of 4e2/πh (where Planck's constant and the electron charge are denoted by h and e, respectively.). This transport property can be used to justify chaotic quantum systems and ballistic transistors. Our theoretical results demonstrate that the local density of state of the graphene sheet for EL = ER = 0 is larger than EL = ER = t (where EL (ER) is onsite energy of the left (right) metallic lead) unlike the current obtained from the calculations.


Author(s):  
W. F. Chagas-Filho

We present a generalization of the first-order formalism used to describe the dynamics of a classical system. The generalization is then applied to the first-order action that describes General Relativity. As a result we obtain equations that can be interpreted as describing quantum gravity in the momentum representation.


2021 ◽  
Vol 5 (2) ◽  
Author(s):  
Siti Sahara ◽  
Sugeng Priyanto

Currently, Covid-19 is a hot topic of conversation in all countries, including Indonesia. In Indonesia itself, a Large-Scale Social Restriction (PSBB) policy was implemented to suppress the spread of this virus so that all activities carried out outside the home must be stopped until this pandemic has subsided. The imposition of Large-Scale Social Restrictions (PSBB) made the learning system change from a classical system to a Distance Learning (PJJ) or online system. In the Introduction to Management course, student participation was found to be low during the learning process. Lecturers have difficulty determining whether students take learning seriously or not. Often in distance learning, some students deliberately put up a video that has been recorded, so that it seems like they are following the learning process, but in reality, they are doing something else. This is caused by several factors, including media which can be in the form of video lessons and student interest in learning. Looking at the description above, researchers are interested in conducting research that aims to determine the effect of using video learning and learning interest on learning outcomes in the Management Introduction course in the distance learning process during the Covid 19 pandemic. This research was conducted in the D3 Transportation Study Program, Faculty of Engineering, the State University of Jakarta in semester 113 of the 2020/2021 school year. This research is an ex post facto research with a quantitative approach. The number of samples in this study consisted of 76 students. The data collection technique is done by using questionnaires and documentation. The data obtained were analyzed using a multiple regression test. The results of this study indicate that Fcount ≥ Ftable = 13.53 ≥ 3.124 so it can be concluded that there is a significant influence between the use of instructional videos (X1) and interest (X2) on learning outcomes in the Introduction to Management (Y) course. For this reason, the role of lecturers is indispensable in continuously making creative innovations in developing various kinds of learning media that can increase student interest in learning during the Covid 19 pandemic. 


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