Characterization and optimized engineering of bosonic quantum interfaces under single-mode operational constraints

Fuente: arXiv
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Main Authors: Fong, Pak-Tik, Poon, Sheung Chi, Lau, Hoi-Kwan
Format: Preprint
Published: 2022
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author Fong, Pak-Tik
Poon, Sheung Chi
Lau, Hoi-Kwan
author_facet Fong, Pak-Tik
Poon, Sheung Chi
Lau, Hoi-Kwan
contents Controlling the quantum interface between two bosonic modes is essential in countless implementations of quantum information processing. However, full controllability is rarely achieved in most platforms due to specific physical limitations. In this work, we completely characterize the linear two-mode interfaces under the most pessimistic restriction that only single-mode operation is available. When arbitrary Gaussian single-mode operations can be applied to both modes, we find that every interface can be characterized by an invariant transmission strength. Moreover, in the practical situation that squeezing is restricted in one of the modes, we discover two additional quantities, irreducible squeezing and irreducible shearing, that are invariant under the allowable controls. By using this characterization, we develop systematic strategies to engineer an arbitrary linear interface through cascading multiple fixed component interfaces. Without squeezing restriction, our protocol is optimal and requires at most three component interfaces. Under the squeezing constraint, our protocol can be extended to engineer also the additional invariants by using no more than two more rounds of cascade. We also propose the remote squeezing scheme to tackle the squeezing restriction through interfacing with an active auxiliary mode.
format Preprint
id arxiv_https___arxiv_org_abs_2212_05134
institution arXiv
publishDate 2022
record_format arxiv
spellingShingle Characterization and optimized engineering of bosonic quantum interfaces under single-mode operational constraints
Fong, Pak-Tik
Poon, Sheung Chi
Lau, Hoi-Kwan
Quantum Physics
Controlling the quantum interface between two bosonic modes is essential in countless implementations of quantum information processing. However, full controllability is rarely achieved in most platforms due to specific physical limitations. In this work, we completely characterize the linear two-mode interfaces under the most pessimistic restriction that only single-mode operation is available. When arbitrary Gaussian single-mode operations can be applied to both modes, we find that every interface can be characterized by an invariant transmission strength. Moreover, in the practical situation that squeezing is restricted in one of the modes, we discover two additional quantities, irreducible squeezing and irreducible shearing, that are invariant under the allowable controls. By using this characterization, we develop systematic strategies to engineer an arbitrary linear interface through cascading multiple fixed component interfaces. Without squeezing restriction, our protocol is optimal and requires at most three component interfaces. Under the squeezing constraint, our protocol can be extended to engineer also the additional invariants by using no more than two more rounds of cascade. We also propose the remote squeezing scheme to tackle the squeezing restriction through interfacing with an active auxiliary mode.
title Characterization and optimized engineering of bosonic quantum interfaces under single-mode operational constraints
topic Quantum Physics
url https://arxiv.org/abs/2212.05134