July 31, 2023 to August 4, 2023
Perimeter Institute for Theoretical Physics
America/Toronto timezone

Talk 118 - Overlapping qubits from non-isometric maps and de Sitter tensor networks

Aug 4, 2023, 10:00 AM
PI/1-100 - Theatre (Perimeter Institute for Theoretical Physics)

PI/1-100 - Theatre

Perimeter Institute for Theoretical Physics



Alexander Jahn (Free University of Berlin)


We construct approximately local observables, or "overlapping qubits", using non-isometric maps and show that processes in local effective theories can be spoofed with a quantum system with fewer degrees of freedom, similar to our expectation in holography. Furthermore, the spoofed system naturally deviates from an actual local theory in ways that can be identified with features in quantum gravity. For a concrete example, we construct two MERA toy models of de Sitter space-time and explain how the exponential expansion in global de Sitter can be spoofed with many fewer quantum degrees of freedom and that local physics may be approximately preserved for an exceedingly long time before breaking down. Conceptually, we comment on how approximate overlapping qubits connect Hilbert space dimension verification, degree-of-freedom counting in black holes and holography, approximate locality in quantum gravity, non-isometric codes, and circuit complexity.

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