**Dynamic Casimir Phenomena**

**Accelerating bodies in vacuum may experience friction, and emit radiation.**

"Quantum Theory of the Electromagnetic Field in a Variable-Length One-Dimensional Cavity,"

G. T. Moore, J. Math. Phys.

11, 2679 (1970)"Radiation from a Moving Mirror in Two Dimensional Space-Time: Conformal Anomaly,"

S. A. Fulling and P. C. W. Davies, Proc. R. Soc. London, Ser. A 348, 393 (1976).

..."Observation of the dynamical Casimir effect in a superconducting circuit,"

C.M. Wilson, G. Johansson, A. Pourkabirian, M. Simoen, J.R. Johansson, T. Duty, F. Nori & P. Delsing, Nature

479, 376 (2011).

**Stationary (time invariant) moving states:**

"Shearing the vacuum - quantum friction,"

J.B. Pendry, J. Phys.: Condens. Matter

9, 10301 (1997)."Near-field radiative heat transfer and noncontact friction,"

A. I. Volokitin and B. N. J. Persson, Rev. Mod. Phys.

79, 1291 (2007).

**Rotation: **Consider waves of frequency ω and angular state *m* impinging on object rotating with frequency Ω

"Generation of waves by a rotating body,"Lab frame:

Object frame:

Ya B. Zel'dovich, JETP Lett.

14, 180 (1971); If ω' and ω have opposite signs:Amplitude of (classical) scattered wave exceeds incoming wave (

Super-radiance).Conjectured (quantum) spontaneous emission with no incoming wave.

"Spontaneous emission by rotating objects: A scattering approach,"

M.F. Maghrebi, R.L. Jaffe, & M. Kardar, PRL

108, 230403 (2012).Number of photons in a mode of frequency

ωand angular momentumm,generated by object rotating with angular velocity

Ωis:

E.g., net power for a rotating cylinder:

The rotating cylinder also drags and spins small test bodies in its vicinity.