scholarly journals Accelerating universe in brane gravity with a confining potential

2006 ◽  
Vol 640 (1-2) ◽  
pp. 1-6 ◽  
Author(s):  
M. Heydari-Fard ◽  
M. Shirazi ◽  
S. Jalalzadeh ◽  
H.R. Sepangi
Keyword(s):  
Accelerating Universe ◽  
Confining Potential ◽  
Brane Gravity

scholarly journals Gauss-Bonnet brane gravity with a confining potential

2007 ◽  
Vol 75 (6) ◽  
Author(s):  
M. Heydari-Fard ◽  
H. R. Sepangi
Keyword(s):  
Confining Potential ◽  
Brane Gravity

scholarly journals Anisotropic brane gravity with a confining potential

2007 ◽  
Vol 649 (1) ◽  
pp. 1-11 ◽  
Author(s):  
M. Heydari-Fard ◽  
H.R. Sepangi
Keyword(s):  
Confining Potential ◽  
Brane Gravity

scholarly journals Accelerating universe in f(R) brane gravity

2008 ◽  
Vol 660 (4) ◽  
pp. 275-281 ◽  
Author(s):  
K. Atazadeh ◽  
M. Farhoudi ◽  
H.R. Sepangi
Keyword(s):  
Accelerating Universe ◽  
Brane Gravity

Effective Dielectric Function of Porous Silicon: the Transverse Component

1994 ◽  
Vol 358 ◽  
Author(s):  
G. Gumbs
Keyword(s):  
Absorption Spectrum ◽  
Absorption Coefficient ◽  
Electron Density ◽  
Quantum Wires ◽  
Interband Transition ◽  
Incident Light ◽  
Transverse Component ◽  
Effect Of Temperature ◽  
High Electron ◽  
Confining Potential

ABSTRACTA self-consistent many-body theory is developed to study the effect of temperature and electron density on the interband absorption coefficient and the frequency-dependent refractive index for an array of isolated quantum wires. The peaks in the absorption coefficient correspond to interband transitions resulting in the resonant absorption of light. The oscillations in the derivative spectrum are due to the quantization of the energy levels related to the in-plane confining potential for such reduced dimensional systems. There are appreciable changes in the absorption spectrum when the electron density or temperature is increased. One interband transition peak is suppressed in the high electron density limit and the thermal depopulation effect on the electron subbands can be easily seen when the temperature is high. We also find that the exciton coupling weakens the shoulder features in the absorption spectrum. This study is relevant to optical characterization of the confining potential and the areal density of electrons using photoreflectance. By using incident light with tunable frequencies in the interband excitation regime, contactless photoreflectance measurements may be carried out and the data compared with our calculations. By fitting the numerical results to the peak positions of the photoreflectance spectrum, the number of electrons in each wire may be extracted.

scholarly journals Shift a laser beam back and forth to exchange heat and work in thermodynamics

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
John A. C. Albay ◽  
Zhi-Yi Zhou ◽  
Cheng-Hung Chang ◽  
Yonggun Jun
Keyword(s):  
Optical Feedback ◽  
Brownian Particle ◽  
Time Varying ◽  
Optical Technique ◽  
Work Related ◽  
Engine Efficiency ◽  
Confining Potential ◽  
Equipartition Theorem ◽  
Virtual Temperature ◽  
High Flexibility

AbstractAlthough the equivalence of heat and work has been unveiled since Joule’s ingenious experiment in 1845, they rarely originate from the same source in experiments. In this study, we theoretically and experimentally demonstrated how to use a high-precision optical feedback trap to combine the generation of virtual temperature and potential to simultaneously manipulate the heat and work of a small system. This idea was applied to a microscopic Stirling engine consisting of a Brownian particle under a time-varying confining potential and temperature. The experimental results justified the position and the velocity equipartition theorem, confirmed several theoretically predicted energetics, and revealed the engine efficiency as well as its trade-off relation with the output power. The small theory–experiment discrepancy and high flexibility of the swift change of the particle condition highlight the advantage of this optical technique and prove it to be an efficient way for exploring heat and work-related issues in the modern thermodynamics for small systems.

scholarly journals Action principle for action-dependent Lagrangians toward nonconservative gravity: Accelerating universe without dark energy

2017 ◽  
Vol 95 (10) ◽  
Author(s):  
Matheus J. Lazo ◽  
Juilson Paiva ◽  
João T. S. Amaral ◽  
Gastão S. F. Frederico
Keyword(s):  
Dark Energy ◽  
Action Principle ◽  
Accelerating Universe
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