Suppressing Quantum Fluctuations in Classicalization

Who: Alexander Vikman (CERN & Stanford University)
When: Wednesday, February 20, 2013 at 14:15
Where: U49

Following my recent paper  arXiv:1208.3647, I will start by reviewing one of the cornerstones of quantum mechanics uncertainty relations. Further, I formulate the uncertainty relations in QFT. Then I will discuss vacuum quantum fluctuations of simple Nambu-Goldstone bosons derivatively coupled single scalar field theories possessing shift symmetry in field space. I will argue that quantum fluctuations of the interacting field can be drastically suppressed with respect to the free field case. Moreover, the power-spectrum of these fluctuations can soften to become red for sufficiently small scales. In quasiclassical approximation, it is demonstrated that this suppression can only occur for those theories that admit such classical static backgrounds around which small perturbations propagate faster than light. Thus a quasiclassical softening of quantum fluctuations is only possible for theories which classicalize instead of having a usual Lorentz invariant and local Wilsonian UV-completion. I will illustrate this analysis by estimating the quantum fluctuations for the DBI-like theories.

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