Exponentially-improved effective descriptions of physical bosonic systems

Fuente: arXiv
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Main Authors: Upreti, Varun, Quesada, Nicolás, Chabaud, Ulysse
Format: Preprint
Published: 2026
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author Upreti, Varun
Quesada, Nicolás
Chabaud, Ulysse
author_facet Upreti, Varun
Quesada, Nicolás
Chabaud, Ulysse
contents The effective description of a bosonic quantum system identifies the minimum finite dimension required to capture its essential dynamics. This effective dimension plays an important role in the complexity of classical and quantum algorithms for learning and simulating bosonic systems. While generic bosonic states require a dimension scaling as $1/ε^2$ for a precision of approximation $ε$, here we identify a natural energy condition which allows us to improve this scaling exponentially to $\log(1/ε)$. We then prove that most bosonic quantum states satisfy this condition, and in particular those produced by combining Gaussian dynamics with generic energy-preserving dynamics, which include the output states of universal bosonic quantum circuits. We apply this finding to enhance learning algorithms for bosonic quantum states and we further obtain new classical simulation algorithms for a large class of bosonic systems. Finally, using efficient decompositions of Kerr gates as sums of Gaussian gates, we significantly refine these classical simulation algorithms for universal bosonic quantum circuits. Our results demonstrate that physical bosonic systems are significantly more well-behaved than previously assumed, allowing for efficient descriptions even at high precision.
format Preprint
id arxiv_https___arxiv_org_abs_2604_18720
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Exponentially-improved effective descriptions of physical bosonic systems
Upreti, Varun
Quesada, Nicolás
Chabaud, Ulysse
Quantum Physics
The effective description of a bosonic quantum system identifies the minimum finite dimension required to capture its essential dynamics. This effective dimension plays an important role in the complexity of classical and quantum algorithms for learning and simulating bosonic systems. While generic bosonic states require a dimension scaling as $1/ε^2$ for a precision of approximation $ε$, here we identify a natural energy condition which allows us to improve this scaling exponentially to $\log(1/ε)$. We then prove that most bosonic quantum states satisfy this condition, and in particular those produced by combining Gaussian dynamics with generic energy-preserving dynamics, which include the output states of universal bosonic quantum circuits. We apply this finding to enhance learning algorithms for bosonic quantum states and we further obtain new classical simulation algorithms for a large class of bosonic systems. Finally, using efficient decompositions of Kerr gates as sums of Gaussian gates, we significantly refine these classical simulation algorithms for universal bosonic quantum circuits. Our results demonstrate that physical bosonic systems are significantly more well-behaved than previously assumed, allowing for efficient descriptions even at high precision.
title Exponentially-improved effective descriptions of physical bosonic systems
topic Quantum Physics
url https://arxiv.org/abs/2604.18720