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SUMMARY:Probing sign structure using measurement-induced entanglement
DTSTART;VALUE=DATE-TIME:20220518T151500Z
DTEND;VALUE=DATE-TIME:20220518T160000Z
DTSTAMP;VALUE=DATE-TIME:20221004T163336Z
UID:indico-contribution-176@events.perimeterinstitute.ca
DESCRIPTION:Speakers: Tim Hsieh (Perimeter Institute)\nThe sign structure
of quantum states is closely connected to quantum phases of matter\, yet d
etecting such fine-grained properties of amplitudes is subtle. We employ
as a diagnostic measurement-induced entanglement (MIE)-- the average entan
glement generated between two parties after measuring the rest of the syst
em. We propose that for a sign-free state\, the MIE upon measuring in the
sign-free basis decays no slower than correlations in the state before me
asurement. Concretely\, we prove that MIE is upper bounded by mutual info
rmation for sign-free stabilizer states (essentially CSS codes)\, which es
tablishes a bound between scaling dimensions of conformal field theories d
escribing measurement-induced critical points in stabilizer systems. We a
lso show that for sign-free qubit wavefunctions\, MIE between two qubits i
s upper bounded by a simple two-point correlation function\, and we verify
our proposal in several critical ground states of one-dimensional systems
\, including the transverse field and tri-critical Ising models. In contr
ast\, for states with sign structure\, such bounds can be violated\, as we
illustrate in critical hybrid circuits involving both Haar or Clifford ra
ndom unitaries and measurements\, and gapless symmetry-protected topologic
al states.\n\nhttps://events.perimeterinstitute.ca/event/11/contributions/
176/
LOCATION:
URL:https://events.perimeterinstitute.ca/event/11/contributions/176/
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