Magnon heralding in cavity optomagnonics
TL;DR: In this paper, a magnon-heralding protocol was proposed to generate a high fidelity magnon Fock state by detecting an optical cavity photon, which was shown that the nonclassical character of the heralded state is only limited by the magnon lifetime for small enough temperatures.
Abstract: In the emerging field of cavity optomagnonics, photons are coupled coherently to magnons in solid-state systems. These new systems are promising for implementing hybrid quantum technologies. Being able to prepare Fock states in such platforms is an essential step towards the implementation of quantum information schemes. We propose a magnon-heralding protocol to generate a magnon Fock state by detecting an optical cavity photon. Due to the peculiarities of the optomagnonic coupling, the protocol involves two distinct cavity photon modes. Solving the quantum Langevin equations of the coupled system, we show that the temporal scale of the heralding is governed by the magnon-photon cooperativity and derive the requirements for generating high fidelity magnon Fock states. We show that the nonclassical character of the heralded state, which is imprinted in the autocorrelation of an optical ``read'' mode, is only limited by the magnon lifetime for small enough temperatures. We address the detrimental effects of nonvacuum initial states, showing that high fidelity Fock states can be achieved by actively cooling the system prior to the protocol.
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TL;DR: In this paper , the authors discuss how magnonic systems can be integrated and entangled with quantum platforms including cavity photons, superconducting qubits, nitrogen-vacancy centers and phonons for coherent information transfer and collaborative information processing.
90 citations
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TL;DR: In this article, the authors discuss how magnonic systems can be integrated and entangled with quantum platforms including cavity photons, superconducting qubits, nitrogen-vacancy centers and phonons for coherent information transfer and collaborative information processing.
Abstract: Spintronics and quantum information science are two promising candidates for innovating information processing technologies. The combination of these two fields enables us to build solid-state platforms for studying quantum phenomena and for realizing multi-functional quantum tasks. For a long time, however, the intersection of these two fields was limited. This situation has changed significantly over the last few years because of the remarkable progress in coding and processing information using magnons. On the other hand, significant advances in understanding the entanglement of quasi-particles and in designing high-quality qubits and photonic cavities for quantum information processing provide physical platforms to integrate magnons with quantum systems. From these endeavours, the highly interdisciplinary field of quantum magnonics emerges, which combines spintronics, quantum optics and quantum information science.Here, we give an overview of the recent developments concerning the quantum states of magnons and their hybridization with mature quantum platforms. First, we review the basic concepts of magnons and quantum entanglement and discuss the generation and manipulation of quantum states of magnons, such as single-magnon states, squeezed states and quantum many-body states including Bose-Einstein condensation and the resulting spin superfluidity. We discuss how magnonic systems can be integrated and entangled with quantum platforms including cavity photons, superconducting qubits, nitrogen-vacancy centers, and phonons for coherent information transfer and collaborative information processing. The implications of these hybrid quantum systems for non-Hermitian physics and parity-time symmetry are highlighted, together with applications in quantum memories and high-precision measurements. Finally, we present an outlook on the opportunities in quantum magnonics.
90 citations
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TL;DR: Cavity magnonics as mentioned in this paper deals with the interaction of magnons and magnetic materials and confined electromagnetic fields, and is a young field that is gearing up for integration in future quantum technologies.
63 citations
TL;DR: In this article, the authors proposed two different mechanisms for observing the magnon blockade effect in the ferromagnetic sphere and showed that the much stronger magnon antibunching with significantly increased steady-state mean magnon numbers can be realized by the destructive interference for the two-magnon excitation.
Abstract: We study the generation of a magnon blockade in a single-crystalline yttrium-iron-garnet (YIG) sphere coupled to a three-dimensional superconducting microwave resonator that interacts with a superconducting qubit. Based on the indirect coupling between the Kittel mode of YIG and the superconducting qubit mediated by the virtual photon excitation in the microwave cavity, we propose two different mechanisms for observing the magnon blockade effect in the ferromagnetic sphere. The first one is to use the strong anharmonicity of the dressed states of the coupled qubit-magnon system. However, the strong magnon antibunching can only be achieved under the strong-coupling regime. To relax this constraint, we propose another quantum interference method to produce and enhance the magnon blockade effect with the moderate-coupling strength. By optimizing the relative phase and the strength ratio of the external driving fields applied to the YIG and qubit, we show that the much stronger magnon antibunching with significantly increased steady-state mean magnon numbers can be realized by the destructive interference for the two-magnon excitation.
52 citations
TL;DR: In this paper, the authors proposed an approach to remotely prepare magnon even or odd cat states by performing local non-Gaussian operations on the optical mode that is entangled with the magnon mode through pulsed optomagnonic interaction.
Abstract: The magnon cat state represents a macroscopic quantum superposition of collective magnetic excitations of large number spins that not only provides fundamental tests of macroscopic quantum effects but also finds applications in quantum metrology and quantum computation. In particular, remote generation and manipulation of Schr\"odinger cat states are particularly interesting for the development of long-distance and large-scale quantum information processing. Here, we propose an approach to remotely prepare magnon even or odd cat states by performing local non-Gaussian operations on the optical mode that is entangled with the magnon mode through pulsed optomagnonic interaction. By evaluating key properties of the resulting cat states, we show that for experimentally feasible parameters, they are generated with both high fidelity and nonclassicality, as well as with a size large enough to be useful for quantum technologies. Furthermore, the effects of experimental imperfections such as the error of projective measurements and dark count when performing single-photon operations have been discussed, where the lifetime of the created magnon cat states is expected to be $t\ensuremath{\sim}1\text{ }\text{ }\ensuremath{\mu}\mathrm{s}$.
43 citations
References
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Journal Article•
28,685 citations
01 Dec 2010
TL;DR: This chapter discusses quantum information theory, public-key cryptography and the RSA cryptosystem, and the proof of Lieb's theorem.
Abstract: Part I. Fundamental Concepts: 1. Introduction and overview 2. Introduction to quantum mechanics 3. Introduction to computer science Part II. Quantum Computation: 4. Quantum circuits 5. The quantum Fourier transform and its application 6. Quantum search algorithms 7. Quantum computers: physical realization Part III. Quantum Information: 8. Quantum noise and quantum operations 9. Distance measures for quantum information 10. Quantum error-correction 11. Entropy and information 12. Quantum information theory Appendices References Index.
14,825 citations
TL;DR: In this paper, the authors introduce magnetostatics and magnetism of localized electrons on the atom, and apply it to spin electronics and magnetic recording, as well as applications of hard magnets.
Abstract: 1. Introduction 2. Magnetostatics 3. Magnetism of electrons 4. Magnetism of localized electrons on the atom 5. Ferromagnetism and exchange 6. Antiferromagnetism and other magnetic order 7. Micromagnetism, domains and hysteresis 8. Nanoscale magnetism 9. Magnetic resonance 10. Experimental methods 11. Magnetic materials 12. Applications of soft magnets 13. Applications of hard magnets 14. Spin electronics and magnetic recording 15. Special topics Appendixes Index.
3,137 citations
TL;DR: It is shown that the communication efficiency scales polynomially with the channel length, and hence the scheme should be operable over very long distances.
Abstract: Quantum communication holds promise for absolutely secure transmission of secret messages and the faithful transfer of unknown quantum states. Photonic channels appear to be very attractive for the physical implementation of quantum communication. However, owing to losses and decoherence in the channel, the communication fidelity decreases exponentially with the channel length. Here we describe a scheme that allows the implementation of robust quantum communication over long lossy channels. The scheme involves laser manipulation of atomic ensembles, beam splitters, and single-photon detectors with moderate efficiencies, and is therefore compatible with current experimental technology. We show that the communication efficiency scales polynomially with the channel length, and hence the scheme should be operable over very long distances.
3,126 citations
TL;DR: In this paper, a reformulation of the phenomenological theory of the magnetization field was proposed to take large non-eddy-current damping into account in thin Permalloy sheets.
Abstract: In 1955, a phenomenological theory of ferromagnetism was well established and had been corroborated by a considerable amount of experimental data. However, there were problems in the phenomenological theory of the dynamics of the magnetization field. The Landau-Lifshitz equation for damping of the motion of the magnetization field could not account for the large noneddy-current damping in thin Permalloy sheets. The problem undertaken herein is a reformulation of the theory in a way that is more consistent with the theory of damping in other physical systems in order to be able to take large damping into account.
2,181 citations