Phononic entanglement concentration via optomechanical interactions

Abstract

Low dissipation, tunable coupling to other quantum systems, and unique features of phonons in the aspects of propagation, detection and others suggest the applications of quantized mechanical resonators in phonon-based quantum information processing (QIP) in a way different from their photonic counterpart. In this paper, we propose the first protocol of entanglement concentration for nonlocal phonons from quantized mechanical vibration. We combine the optomechanical cross-Kerr interaction with the Mach-Zehnder interferometer and, by means of twice optomechanical interactions and the photon analysis with respect to the output of the interferometer, achieve ideal entanglement concentration about less-entangled nonlocal phonon Bell and Greenberger-Horne-Zeilinger states. Our protocol is useful for preserving the entangled phonons for the use of high quality phonon-based QIP in future.PACS numbers: I. INTRODUCTIONQuantum entanglement is a quantum resource indispensable in the areas, such as quantum key distribution [1-3], quantum teleportation [4], quantum secure direct communication [5][6][7][8] and quantum dense coding [9,10]. In quantum communications, an entangled state is usually used for building a quantum channel between remote parties. However, the channel noise will induce decoherence and degrade the entanglement between the quantum systems. Entanglement concentration [11][12][13][14][15][16][17][18][19][20][21][22][23] is an operation which converts a partially entangled state to a more or maximally entangled state. Since the first entanglement concentration protocol (ECP), the well known Schmidt projection, was proposed by Bennett et al [11], its realization on the various physical systems has been reported. The examples include ECPs with linear optical elements in the principle of Schmidt projection [12,13], nonlocal-photon ECP with linear [17] or nonlinear optical elements [18,19], and ECP based on electron-spin systems [20] or on circuit quantum electrodynamics [21,22], etc.

Hyperentanglement-assisted hyperdistillation for hyper-encoding photon system

“…Entanglement (hyperentanglement) concentration is introduced to distill maximally (hyper)entangled state from partially (hyper)entangled state [53]. Since the first entanglement concentration protocol was proposed by Bennet et al using collective measurement [53], many entanglement concentration protocols have been proposed for photon system using linear optical elements [54][55][56][57][58] and nonlinear optical elements [59][60][61][62][63], and some of the entanglement concentration protocols have been demonstrated experimentally using linear optical elements [54,55]. Hyperentanglement concentration protocols [64][65][66][67][68][69][70][71][72] have also attracted much attention for recovering the partially hyperentangled state to maximally hyperentangled state with certain success probability.…”

Multimode Interference Induced Optical Routing in an Optical Microcavity

“…As a promising platform for realizing quantum electrodynamics, cavity optomechanics in optical microcavity have been widely investigated theoretically and experimentally. [14][15][16][17][18][19] Early studies are restricted to basic optomechanical models with one optical mode and one mechanical mode, models with multimode interaction, which couples multiple optical modes to a mechanical mode, exhibit richer physics DOI: 10.1002/andp.202000506 phenomena such as optomechanical induced transparency (OMIT) [20][21][22][23][24][25][26][27] and absorption (OMIA) [28,29] and shows enormous potential in applications ranging from quantum information processing, [30][31][32][33][34][35][36][37][38][39] state transfers [40][41][42] to optomechanically induced nonreciprocity. [43][44][45][46][47][48][49][50][51] Optical router is a key element for controlling the path of signal flow in quantum and classical network.…”

Entanglement Concentration Protocols for GHZ-type Entangled Coherent State Based on Linear Optics

“…Along with the state generation [27,28], GHZ state has been popular for the realization of various applications [29][30][31] in discreet variable (DV) domain where the entanglement is encoded in polarization of photons. For the perfect execution of such GHZ state applications numerous ECPs have also been introduced recently [24,[32][33][34] [and references therein]. Interestingly, in the similar way, GHZ state also has its significant importance in continuous variable (CV) domain where the entanglement is encoded in superposition of coherent states | ± α (α being amplitude with large values).…”