نتایج جستجو برای: casimir effect

تعداد نتایج: 1644549  

1998
M. V. Cougo - Pinto C. Farina M. R. Negrão

We compute the influence of an applied magnetic field on the Casimir energy of a massive scalar field confined between two parallel infinite plates using Schwinger's method from source theory. The boundary conditions are those of a vanishing field through the plates. The obtained results show that a strong magnetic field inhibits the bosonic Casimir effect and that a weak magnetic field increas...

2000
Feng-Li Lin

In this note we calculate the Casimir effect of free thermal gravitons in Einstein universe and discuss how it changes the entropy bound condition proposed recently by Verlinde as a higher dimensional generalization of Cardy’s formula for conformal field theories (CFT). We find that the graviton’s Casimir effect is necessary in order not to violate Verlinde’s bound for weakly coupled CFT. We al...

2006
Iver Brevik Simen A Ellingsen Kimball A Milton

The Casimir effect, reflecting quantum vacuum fluctuations in the electromagnetic field in a region with material boundaries, has been studied both theoretically and experimentally since 1948. The forces between dielectric and metallic surfaces both plane and curved have been measured at the 10 to 1 percent level in a variety of room-temperature experiments, and remarkable agreement with the ze...

2007
R. C. Batra M. Porfiri D. Spinello

We analyze pull-in instability of electrostatically actuated microelectromechanical systems, and study changes in pull-in parameters due to the Casimir effect. When the size of the device is reduced, the magnitude of the Casimir force is comparable with that of the Coulomb force and it significantly alters pull-in parameters. We model the deformable conductor as an elastic membrane and consider...

2010
Olesya Gorbunova Diego Sáez-Gómez

The role of dynamical cosmological Casimir effect to phantom (constant w ) and oscillating universe is discussed. It is shown explicitly that its role is not essential near to Big Rip singularity. However, the account of Casimir fluid makes the scale factor approach to Rip time to be faster. Rip time itself maybe changed too.

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه شیراز - دانشکده علوم 1369

در درجه حرارتهای خیلی پائین پویش آزاد فوتون ها در یک کریستال خالص عا توسط پراش از سطوح مرزی محدود میگردد. برای اولین بار محاسبه پویش آزاد فوتون ناشی از پراش مرزی توسط casimir انجام گرفت . در این رساله ما با استفاده از تئوری casimir این محاسبات را بر روی نمونه مکعب مستطیل با ابعاد محدود و نمونه کریستالی دیسکی شکل انجام داده و نهایتا" نتایج بدست آمده با نتایج تجربی مقایسه گردیده که کاملا" مطابقت ...

2006
Robson B. Rodrigues Paulo A. Maia Neto

– We study the torque arising between two corrugated metallic plates due to the interaction with electromagnetic vacuum. This Casimir torque can be measured with torsion pendulum techniques for separation distances as large as 1μm. It allows one to probe the nontrivial geometry dependence of the Casimir energy in a configuration which can be evaluated theoretically with accuracy. In the optimal...

2008
Hongbo Cheng

A one-dimensional Casimir piston for massless scalar fields obeying Dirichlet boundary conditions in high-dimensional spacetimes within the frame of Kaluza-Klein theory is analyzed. We derive and calculate the exact expression for the Casimir force on the piston. We also compute the Casimir force in the limit that one outer plate is moved to the extremely distant place to show that the reduced ...

2001
M. R. Setare

The Casimir stress on two concentric spherical shell in de Sitter background for massless scalar field is calculated. The scalar field satisfies Dirichlet boundary conditions on the spheres. The metric is written in conformally flat form to make maximum use of Minkowski space calculations. Then the Casimir stress is calculated for inside and outside of the shell with different backgrounds. This...

Journal: :Science 2001
H B Chan V A Aksyuk R N Kleiman D J Bishop F Capasso

The Casimir force is the attraction between uncharged metallic surfaces as a result of quantum mechanical vacuum fluctuations of the electromagnetic field. We demonstrate the Casimir effect in microelectromechanical systems using a micromachined torsional device. Attraction between a polysilicon plate and a spherical metallic surface results in a torque that rotates the plate about two thin tor...

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