Superpositions of Quantum Gaussian Processes

Fuente: arXiv
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Main Authors: Braccini, Lorenzo, Bose, Sougato, Serafini, Alessio
Format: Preprint
Published: 2025
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author Braccini, Lorenzo
Bose, Sougato
Serafini, Alessio
author_facet Braccini, Lorenzo
Bose, Sougato
Serafini, Alessio
contents We generalise the Gaussian formalism of Continuous Variable (CV) systems to describe their interactions with qubits/qudits that result in quantum superpositions of Gaussian processes. To this end, we derive a new set of equations in closed form, which allows us to treat hybrid systems' unitary and open dynamics exactly (without truncation), as well as measurements (ideal and noisy). The $N$-qubits $n$-modes entangled states arising during such processes are named Gaussian-Branched Cat States (GCSs). They are fully characterised by their superposed phase-space quantities: sets of generalised complex first moments and covariance matrices, along with the qubit reduced density matrix (QRDM). We showcase our general formalism with two paradigmatic examples: i) measurement-based entanglement of two qubits via a squeezed, leaking, and measured resonator; ii) the generation of the Wigner negativity of a levitated nanoparticle undergoing Stern-Gerlach interferometry in a diffusive environment.
format Preprint
id arxiv_https___arxiv_org_abs_2510_01156
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Superpositions of Quantum Gaussian Processes
Braccini, Lorenzo
Bose, Sougato
Serafini, Alessio
Quantum Physics
We generalise the Gaussian formalism of Continuous Variable (CV) systems to describe their interactions with qubits/qudits that result in quantum superpositions of Gaussian processes. To this end, we derive a new set of equations in closed form, which allows us to treat hybrid systems' unitary and open dynamics exactly (without truncation), as well as measurements (ideal and noisy). The $N$-qubits $n$-modes entangled states arising during such processes are named Gaussian-Branched Cat States (GCSs). They are fully characterised by their superposed phase-space quantities: sets of generalised complex first moments and covariance matrices, along with the qubit reduced density matrix (QRDM). We showcase our general formalism with two paradigmatic examples: i) measurement-based entanglement of two qubits via a squeezed, leaking, and measured resonator; ii) the generation of the Wigner negativity of a levitated nanoparticle undergoing Stern-Gerlach interferometry in a diffusive environment.
title Superpositions of Quantum Gaussian Processes
topic Quantum Physics
url https://arxiv.org/abs/2510.01156