Sen Zhang

Janus field theories from multiple M2 branes

Based on the recent proposal of N = 8 superconformal gauge theories of the multiple M2 branes, we derive (2 + 1)-dimensional supersymmetric Janus field theories with a space-time dependent coupling constant. From the original Bagger-Lambert model, we get a supersymmetric field theory with a similar action to the N D2 branes, but the coupling varies with the space-time as a function of the light-cone coordinate, g(t + x). Half of the supersymmetries can be preserved. We further investigate the M2 brane action deformed by mass and Myers-like terms. In this case, the final Yang-Mills action is deformed by mass and Myers terms, and the coupling behaves as exp(μx) where μ is a constant mass parameter. Weak coupling gauge theory is continuously changed to strong coupling in the large x region.

Generalized conformal symmetry and recovery of SO(8) in multiple M2 and D2 branes

Abstract We investigate conformal symmetries of the Aharony–Bergman–Jafferis–Maldacena (ABJM) theory for multiple M2 branes and the Lorentzian Bagger–Lambert–Gustavsson (L-BLG) theory which can be obtained by taking a scaling limit k ( ≫ N ) → ∞ of the ABJM theory. The conformal symmetry is maintained in the L-BLG by considering general space–time varying solutions to the constraint equations. The dual geometry is reduced to d = 10 AdS 4 × CP 3 in the scaling limit and has the same conformal symmetry. The curvature radius R satisfies l p ( 11 ) ≪ l p ( 10 ) ≪ R ≪ l s ( l p ( d ) and l s are the d-dimensional Planck lengths and the string scale), and the theory is in a region where an α ′ expansion is not valid. We also study how the SO ( 8 ) covariance is recovered in the AdS 4 × CP 3 geometry by taking the scaling limit.

Stochastic analysis of an accelerated charged particle: Transverse fluctuations

An accelerated particle sees the Minkowski vacuum as thermally excited, and the particle moves stochastically due to an interaction with the thermal bath. This interaction fluctuates the particles transverse momenta like the Brownian motion in a heat bath. Because of this fluctuating motion, it has been discussed that the accelerated charged particle emits extra radiation (the Unruh radiation [P. Chen and T. Tajima, Phys. Rev. Lett. 83, 256 (1999).]) in addition to the classical Larmor radiation, and experiments are under planning to detect such radiation by using ultrahigh intensity lasers constructed in near future [P. G. Thirolf, D. Habs, A. Henig, D. Jung, D. Kiefer, C. Lang, J. Schreiber1, C. Maia, G. Schaller, R. Schutzhold, and T. Tajima, Eur. Phys. J. D 55, 379 (2009).][http://www.extreme-light-infrastructure.eu/.]. There are, however, counterarguments that the radiation is canceled by an interference effect between the vacuum fluctuation and the fluctuating motion. In fact, in the case of an internal detector where the Heisenberg equation of motion can be solved exactly, there is no additional radiation after the thermalization is completed [D. J. Raine, D. W. Sciama, and P. G. Grove, Proc. R. Soc. Lond. A 435, 205 (1991).][A. Raval, B. L. Hu, and J. Anglin, Phys. Rev. D 53, 7003 (1996).]. In this paper, we revisit the issue in the case of an accelerated charged particle in the scalar-field analog of QED. We prove the equipartition theorem of transverse momenta by investigating a stochastic motion of the particle, and show that the Unruh radiation is partially canceled by an interference effect.

Quiver Chern-Simons Theories, D3-Branes, and Lorentzian Lie 3-Algebras

We show that the Bagger-Lambert-Gustavsson (BLG) theory with two pairs of negative norm generators is derived from the scaling limit of an orbifolded Aharony-Bergman-JafferisMaldacena (ABJM) theory. The BLG theory with many Lorentzian pairs is known to be reduced to the Dp-brane theory via the Higgs mechanism, so our scaling procedure can be used to derive Dp-branes directly from M2-branes in the field theory language. In this paper, we focus on the D3-brane case and investigate the scaling limits of various quiver Chern-Simons theories obtained from different orbifolding actions. Remarkably, in the case of N = 2 quiver CS theories, the resulting D3-brane action covers a larger region in the parameter space of the complex structure moduli than the N = 4 quiver CS theories. We also investigate how the SL(2 ,Z ) duality transformation is realized in the resultant D3-brane theory. Subject Index: 120, 121, 123, 124, 125

Quantum radiation produced by a uniformly accelerating charged particle in thermal random motion

In this study, we investigate the signature of the Unruh effect in quantum radiation from an accelerated charged particle interacting with vacuum fluctuations. Because a charged particle in uniformly accelerated motion exhibits thermal random motion around the classical trajectory because of the Unruh effect, its quantum radiation might be termed Unruh radiation. We show that the energy flux of the quantum radiation is negative and that its amplitude is smaller than the classical Larmor radiation by a factor of

Quantum radiation from a particle in an accelerated motion coupled to vacuum fluctuations

a/m

Quantum radiation produced by the entanglement of quantum fields

, where

Thermal property in Brownian motion of a particle coupled to vacuum fluctuations

a

Non-equilibrium fluctuations of black hole horizons and the generalized second law

is the acceleration and

Unruh Radiation Produced by a Uniformly Accelerating Charged Particle in Thermal Random Motions

m