Tuesday, November 29 2016
15:30 - 17:00

Alladi Ramakrishnan Hall

The Turbulent Vacuum

A P Balachandran

CMI, Chennai

The following work is jointly done with M.Asorey, F.Lizzi and G.Marmo.

The vacuum state in relativistic quantum field theory is often pictured as devoid of striking properties, as vacuous. But instead the following are true :

1) Atoms or measuring apparatus inserted at space-like distances in vacuum should exhibit no correlations in the above image of the vacuum. But instead if they have localised states with orthogonal wave functions, and atom 1 is in ground state and 2 in an excited state at a space-like distance, either 1 will *never *be affected by 2 via photon emission (which is absurd) or it will be *instantaneously* affected violating causality.

2) Fields in a finite region, no matter how small, acting on the vacuum can produce *any* state in the Hilbert space.

3) Invariance of the vacuum is invariance of the world. (Coleman).

4)There are * no *localised detectors ! ( Implications for a causal quantum information theory ?)

After discussions of the above, we apply them to the Rindler wedge. There we show that photon *cannot* be confined to the wedge : there is information leakage out of the wedge (but no unitarity violation). This happens because in qed , infrared effects break Lorentz invariance . The above result has potential applications to black hole information paradox.

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