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arXiv:1907.07537 · Physical Review A

Non-Gaussian macroscopic entanglement of motion in a hybrid electromechanical device

Najmeh Eshaqi-Sani, Mehdi Khazaei Nezhad, Mehdi Abdi

Published Aug 27, 2019• 1 citation
arXivHTMLPDF

Abstract

We propose a scheme for entangling the motion of two massive objects in a hybrid electromechanical architecture. The entanglement is generated due to the interaction of two mechanical oscillators with a mediating superconducting qubit. We show that the generated macroscopic entangled states are non-Gaussian and their lifetime is limited by coherence time of the qubit. The entanglement is attainable in a wide range of parameters with appropriate control of the qubit. We confirm the performance of our scheme by numerically solving the quantum-optical master equation including sources of noise. The effect of imperfections, such as asymmetries in the coupling rates as well as mechanical thermal noise, is studied and it is shown how they affect the amount and lifetime of the entangled state. Due to the nonlinear nature of the qubit, the initial Gaussian state of mechanical resonators evolves into a quasistationary non-Gaussian state, which is essential for universal quantum information processing in continuous-variable systems. This work, therefore, provides the first step towards a universal continuous-variable quantum network.

DOI
10.1103/physreva.100.023845

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We propose a scheme for entangling the motion of two massive objects in a hybrid electromechanical architecture. The entanglement is generated due to the interaction of two mechanical oscillators with a mediating superconducting qubit. We show that the generated macroscopic entangled states are non-Gaussian and their lifetime is limited by coherence time of the qubit. The entanglement is attainable in a wide range of parameters with appropriate control of the qubit. We confirm the performance of our scheme by numerically solving the quantum-optical master equation including sources of noise. The effect of imperfections, such as asymmetries in the coupling rates as well as mechanical thermal noise, is studied and it is shown how they affect the amount and lifetime of the entangled state. Due to the nonlinear nature of the qubit, the initial Gaussian state of mechanical resonators evolves into a quasistationary non-Gaussian state, which is essential for universal quantum information processing in continuous-variable systems. This work, therefore, provides the first step towards a universal continuous-variable quantum network.
We investigate dynamical generation of macroscopic nonlocal entanglements between two remote massive magnon-superconducting-circuit hybrid systems. Two fiber-coupled microwave cavities are employed to serve as an interaction channel connecting two sets of macroscopic hybrid units each containing a magnon sphere and a superconducting-circuit qubit. The structure of the hybrid system allows the existence of an optimal fiber coupling strength that requests the shortest amount of time to generate a systematic maximal entanglement, which is solely dependent on the couplings of the channel with both magnon and superconducting circuit. Our theoretical results are shown to be within the scope of specific parameters that can be easily achieved with current technology. The noise effects on the implementation of systems are also treated in a general environment suggesting the robustness of our results. Our discrete-variable qubit-like entanglement theory of magnons may lead to direct applications in various quantum information tasks.
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Quantum states of motion are critical components in the second quantum revolution. We investigate the generation and control of non-Gaussian motional states in a tripartite hybrid quantum system consisting of a collection of qubits coupled to a mechanical resonator, which in turn interacts with an externally driven photonic cavity. This hybrid architecture provides a versatile platform for quantum control by integrating nonlinear interactions and multiple control parameters. Operating in the strong coupling regime, we study the transient dynamics resulting from a time-dependent external drive that has a boxcar profile. Starting from coherent states in both the mechanical and cavity subsystems, we show that this drive protocol, combined with time-independent interaction and frequency configurations, leads to the emergence of highly non-Gaussian quantum states in the intermediary mechanical degree of freedom. These states are characterized by a pronounced negative volume in the Wigner quasi-probability distribution and enhanced quantum Fisher information, indicative of their quantum utility. We systematically analyze the impact of the qubit phase, interaction strengths, and drive parameters on the degree of non-Gaussianity. Our findings underscore the tunability and richness of this hybrid platform, paving the way for advanced quantum state engineering and applications in quantum sensing, metrology, and information processing.
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We investigate dynamical generation of macroscopic nonlocal entanglements between two remote massive magnon-superconducting-circuit hybrid systems. Two fiber-coupled microwave cavities are employed to serve as an interaction channel connecting two sets of macroscopic hybrid units, each containing a magnon (hosted by an yttrium-iron-garnet sphere) and a superconducting-circuit qubit. Surprisingly, it is found that stronger coupling does not necessarily mean faster entanglement generation. The proposed hybrid system allows the existence of an optimal fiber coupling strength that requires the shortest amount of time to generate a systematic maximal entanglement. Our theoretical results are shown to be within the scope of specific parameters that can be achieved with current technology. The noise effects on the implementation of systems are also treated in a general environment, suggesting the robustness of entanglement generation. Our discrete-variable qubit-like entanglement theory of magnons may lead to direct applications in various quantum information tasks.