Anticoncentration in Clifford Circuits and Beyond: From Random Tensor Networks to Pseudo-Magic States

Fuente: arXiv
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Autores principales: Magni, Beatrice, Christopoulos, Alexios, De Luca, Andrea, Turkeshi, Xhek
Formato: Preprint
Publicado: 2025
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author Magni, Beatrice
Christopoulos, Alexios
De Luca, Andrea
Turkeshi, Xhek
author_facet Magni, Beatrice
Christopoulos, Alexios
De Luca, Andrea
Turkeshi, Xhek
contents Anticoncentration describes how an ensemble of quantum states spreads over the allowed Hilbert space, leading to statistically uniform output probability distributions. In this work, we investigate the anticoncentration of random Clifford circuits toward the overlap distribution of random stabilizer states. Using exact analytical techniques and extensive numerical simulations based on Clifford replica tensor networks, we demonstrate that random Clifford circuits fully anticoncentrate in logarithmic circuit depth, namely higher-order moments of the overlap distribution converge to those of random stabilizer states. Moreover, we investigate the effect of introducing a controlled number of non-Clifford (magic) resources into Clifford circuits. We show that inserting a polylogarithmic in qudit number of $T$-states is sufficient to drive the overlap distribution toward the Porter-Thomas statistics, effectively recovering full quantum randomness. In short, this fact presents doped tensor networks and shallow Clifford circuits as pseudo-magic quantum states. Our results clarify the interplay between Clifford dynamics, magic-state injection, and quantum complexity, with implications for quantum circuit sampling, many-body quantum physics, and the benchmarking of quantum computational advantage.
format Preprint
id arxiv_https___arxiv_org_abs_2502_20455
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Anticoncentration in Clifford Circuits and Beyond: From Random Tensor Networks to Pseudo-Magic States
Magni, Beatrice
Christopoulos, Alexios
De Luca, Andrea
Turkeshi, Xhek
Quantum Physics
Statistical Mechanics
Anticoncentration describes how an ensemble of quantum states spreads over the allowed Hilbert space, leading to statistically uniform output probability distributions. In this work, we investigate the anticoncentration of random Clifford circuits toward the overlap distribution of random stabilizer states. Using exact analytical techniques and extensive numerical simulations based on Clifford replica tensor networks, we demonstrate that random Clifford circuits fully anticoncentrate in logarithmic circuit depth, namely higher-order moments of the overlap distribution converge to those of random stabilizer states. Moreover, we investigate the effect of introducing a controlled number of non-Clifford (magic) resources into Clifford circuits. We show that inserting a polylogarithmic in qudit number of $T$-states is sufficient to drive the overlap distribution toward the Porter-Thomas statistics, effectively recovering full quantum randomness. In short, this fact presents doped tensor networks and shallow Clifford circuits as pseudo-magic quantum states. Our results clarify the interplay between Clifford dynamics, magic-state injection, and quantum complexity, with implications for quantum circuit sampling, many-body quantum physics, and the benchmarking of quantum computational advantage.
title Anticoncentration in Clifford Circuits and Beyond: From Random Tensor Networks to Pseudo-Magic States
topic Quantum Physics
Statistical Mechanics
url https://arxiv.org/abs/2502.20455