Calculation of spectral determinants

A method for regularizing spectral determinants is developed which facilitates their computation from a finite number of eigenvalues. This is used to calcu­late the determinant ∆ for the hyperbola billiard over a range which includes 46 quantum energy levels. The result is compared with semiclassical periodic orbit evaluations of ∆ using the Dirichlet series, Euler product, and a Riemann-Siegel-type formula. It is found that the Riemann-Siegel-type expansion, which uses the least number of orbits, gives the closest approximation. This provides explicit numerical support for recent conjectures concerning the analytic proper­ties of semiclassical formulae, and in particular for the existence of resummation relations connecting long and short pseudo-orbits.

We study the spectral determinant ∆ ( E ), which has, by construction, zeros at the quantum energy levels of a given system. If the classical motion of the system in question is chaotic then ∆ ( E ) has a semiclassical representation as a sum over combinations of periodic orbits. There are, however, a number of fundamental problems associated with its convergence properties. Imposing upon the sum the condition that, like ∆ ( E ) itself, it is real for real E , we obtain formal resummation equations relating the contributions from asymptotically long orbits to those of the short orbits. These then lead to a formal derivation of the previously conjectured ‘Riemann-Siegel lookalike’ formula, which involves only a finite orbit sum and thus represents, in principle, a semiclassical rule for quantizing chaos.


2011 ◽  
Vol 25 (06) ◽  
pp. 413-418
Author(s):  
JI-SUO WANG ◽  
KE-ZHU YAN ◽  
BAO-LONG LIANG

Starting from the classical equation of the motion of a domain wall in the ferromagnetic systems, the quantum energy levels of the wall and the corresponding eigenfunctions in the case of considering damping term are given by using the canonical quantization method and unitary transformation. The quantum fluctuations of displacement and momentum of the moving wall has also been given as well as the uncertain relation.


2016 ◽  
Vol 30 (13) ◽  
pp. 1642008 ◽  
Author(s):  
S. P. Kruchinin

Recent experiments have fabricated structured arrays. We study hybrid nanowires, in which normal and superconducting regions are in close proximity, by using the Bogoliubov–de Gennes equations for superconductivity in a cylindrical nanowire. We succeed to obtain the quantum energy levels and wavefunctions of a superconducting nanowire. The obtained spectra of electrons remind Hofstadter’s butterfly.


1997 ◽  
Vol 12 (20) ◽  
pp. 3545-3550 ◽  
Author(s):  
Ion I. Cotăescu

A family of relativistic geometric models is defined as a generalization of the actual anti-de Sitter (1 + 1) model of the relativistic harmonic oscillator. It is shown that all these models lead to the usual harmonic oscillator in the nonrelativistic limit, even though their relativistic behavior is quite different. Among quantum models we find a set of models with countable energy spectra, and another one having only a finite number of energy levels and in addition a continuous spectrum.


2019 ◽  
Vol 40 (9) ◽  
pp. 2571-2592 ◽  
Author(s):  
MAO SHINODA ◽  
HIROKI TAKAHASI

For a non-generic, yet dense subset of$C^{1}$expanding Markov maps of the interval we prove the existence of uncountably many Lyapunov optimizing measures which are ergodic, fully supported and have positive entropy. These measures are equilibrium states for some Hölder continuous potentials. We also prove the existence of another non-generic dense subset for which the optimizing measure is unique and supported on a periodic orbit. A key ingredient is a new$C^{1}$perturbation theorem which allows us to interpolate between expanding Markov maps and the shift map on a finite number of symbols.


1980 ◽  
Vol 21 (4) ◽  
pp. 834-839 ◽  
Author(s):  
L. Nitti ◽  
M. Pellicoro ◽  
M. Villani

2017 ◽  
Vol 31 (25) ◽  
pp. 1745023
Author(s):  
J. T. Wang ◽  
J. D. Fan

In this paper, we carry out a theoretical calculation of quantum state and quantum energy structure in carbon nanotube embedded semiconductor surface. In this theoretical model, the electrons in the carbon nanotube are considered as in a two-dimensional cylindrical surface. Their motion, therefore, can be described by the Dirac equation. We solve the equation and find that the energy levels are quantized and are linearly dependent on the wave vectors along the [Formula: see text]-direction that is along the direction of the nanotube. This type of energy structure may have potential application for fabricating high efficiency solar cell or quantum bit in computer chips.


1990 ◽  
Vol 165-166 ◽  
pp. 947-948
Author(s):  
Paolo Silvestrini ◽  
Luigi Frunzio ◽  
Roberto Cristiano

1993 ◽  
Vol 99 (5) ◽  
pp. 3659-3668 ◽  
Author(s):  
B. Ramachandran ◽  
Kenneth G. Kay
Keyword(s):  

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