Campus Event Calendar

Event Entry

What and Who

Quantum Pseudoentanglement

Adam Bouland
Stanford, Computer Science
INF Distinguished Lecture Series
AG 1, INET, AG 5, RG1, SWS, AG 2, AG 4, D6, AG 3  
MPI Audience

Date, Time and Location

Thursday, 2 March 2023
60 Minutes
Virtual talk
Virtual talk


Abstract: Quantum pseudorandom states are efficiently constructable states which nevertheless masquerade as Haar-random states to poly-time observers. First defined by Ji, Liu and Song, such states have found a number of applications ranging from cryptography to the AdS/CFT correspondence. A fundamental question is exactly how much entanglement is required to create such states. Haar-random states, as well as t-designs for t≥2, exhibit near-maximal entanglement. Here we provide the first construction of pseudorandom states with only polylogarithmic entanglement entropy across an equipartition of the qubits, which is the minimum possible. Our construction can be based on any one-way function secure against quantum attack. We additionally show that the entanglement in our construction is fully "tunable", in the sense that one can have pseudorandom states with entanglement Θ(f(n)) for any desired function ω(logn)≤f(n)≤O(n). More fundamentally, our work calls into question to what extent entanglement is a "feelable" quantity of quantum systems. Inspired by recent work of Gheorghiu and Hoban, we define a new notion which we call "pseudoentanglement", which are ensembles of efficiently constructable quantum states which hide their entanglement entropy. We show such states exist in the strongest form possible while simultaneously being pseudorandom states. We also describe diverse applications of our result from entanglement distillation to property testing to quantum gravity.

Based on joint work with Bill Fefferman, Soumik Ghosh, Umesh Vazirani, and Zixin Zhou, arXiv:2211.00747


Kurt Mehlhorn
+49 681 9325 1025
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Kurt Mehlhorn, 02/06/2023 13:06
Kurt Mehlhorn, 02/02/2023 15:35
Kurt Mehlhorn, 02/02/2023 15:34 -- Created document.