[Paper Review] Quantum-to-classical transition in many-body bosonic interference

Jelmer J. Renema, V. S. Shchesnovich+1 more|arXiv (Cornell University)|Sep 6, 2018

Quantum Information and Cryptography2 citations

TL;DR

This paper proposes a framework to model imperfect multi-boson interference as ideal interference among smaller groups of bosons, with the remaining particles interfering classically. The key result is that the effective quantum interference scale depends only on imperfection levels, not system size, enabling a scalable benchmark for bosonic platforms.

ABSTRACT

Bosonic many-body systems are prominent candidates for a quantum advantage demonstration, with the most popular approaches being either a quantum simulation beyond the reach of current classical computers, or a demonstration of boson sampling. It is a crucial open problem to understand how resilient such quantum advantage demonstrations are to imperfections such as boson loss and particle distinguishability. We partially solve this problem by showing that imperfect multi-boson interference can be efficiently approximated as ideal interference of groups of smaller number of bosons, where the other particles interfere classically. Crucially, the number of bosons undergoing interference in our approxmation only depends on the level of imperfections, but is independent of the actual number of particles. This allows us to construct a simple but stringent benchmark for comparing many-body bosonic technological platforms.

Motivation & Objective

• Understand the resilience of quantum advantage demonstrations in bosonic systems to imperfections like particle distinguishability and loss.
• Address the open problem of how to efficiently model and quantify the impact of imperfections on many-body bosonic interference.
• Develop a benchmark that isolates the quantum contribution to interference independent of system size.
• Provide a framework to compare different many-body bosonic technological platforms under realistic imperfections.

Proposed method

• Model imperfect multi-boson interference as a mixture of ideal interference among smaller groups of bosons and classical interference from the remaining particles.
• Decompose the full many-body state into clusters where only a fixed number of bosons exhibit quantum interference, determined by the imperfection level.
• Use a parameterized approximation where the number of interfering bosons scales with the degree of imperfection, not with the total particle count.
• Formulate the approximation such that the classical background arises from indistinguishable particles that do not contribute to quantum interference.
• Derive a scalable representation of the output probability distribution that separates quantum and classical contributions.
• Validate the approximation by showing it captures the essential features of imperfect interference while remaining computationally efficient.

Experimental results

Research questions

• RQ1 How can imperfect multi-boson interference be efficiently approximated in the presence of particle distinguishability and loss?
• RQ2 What is the effective number of bosons that contribute to quantum interference under given imperfection levels?
• RQ3 Can a benchmark be constructed that isolates the quantum component of interference independent of system size?
• RQ4 How does the structure of interference change when particles are not fully indistinguishable?
• RQ5 To what extent can classical interference account for the observed statistics in imperfect bosonic systems?

Key findings

• Imperfect multi-boson interference can be accurately approximated as ideal interference among a fixed number of bosons, independent of the total system size.
• The number of bosons undergoing quantum interference depends only on the level of imperfections, not on the total number of particles.
• The remaining particles contribute to the output distribution through classical interference, effectively decoupling from the quantum core.
• The proposed approximation enables a scalable benchmark for evaluating the quantum advantage potential of different bosonic platforms.
• The framework provides a clear separation between quantum and classical contributions to interference, simplifying performance evaluation.
• The method remains efficient and predictive even for large systems, as the key parameter is tied to imperfection levels, not system size.