Steve Shenker - Wormholes without averaging

Tuesday 11 May 2021, 17:00 → 19:00 Europe/Zurich

Zoom Only (CERN)

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Abstract:

After averaging over fermion couplings, SYK has a collective field description that sometimes has “wormhole” solutions. We study the fate of these wormholes when the couplings are fixed. Working mainly in a simple model, we find that the wormhole saddles persist, but that new saddles also appear elsewhere in the integration space – “half-wormholes.” The wormhole contributions depend only weakly on the specific choice of couplings, while the half-wormhole contributions are strongly sensitive. The half-wormholes are crucial for factorization of decoupled systems with fixed couplings, but they vanish after averaging, leaving the non-factorizing wormhole behind.    (Joint work with Phil Saad, Douglas Stanford and Shunyu Yao.)

Cern-seminar-2021-given.pdf