Dynamics of Rényi-2 correlations in optomechanics

Abstract

We report on temporal evolution of three different kinds of correlations present between two mechanical resonators of two distant Fabry-Pérot cavities. The two cavities are jointly fed by a two-mode squeezed light and driven by two independent coherent lasers. We consider the initial state of the two mechanical modes as a two-mode uncorrelated thermal state. After evaluating the dynamical covariance matrix elements, we give explicit expressions of the measures of correlations defined via the Rényi-2 entropy, namely, the Rényi-2 quantum mutual information, the Gaussian Rényi-2 entanglement and the Gaussian quantum steering. We find that by an appropriate choice of the system parameters, it is possible to generate entanglement and steering via a quantum correlations transfer from squeezed light to the mechanical bi-mode state. The influence of the squeezing parameter, the optomechanical cooperativity and the environmental thermal noise on the correlations are studied thoroughly. Additionally, we show in various circumstances that the considered temporal correlations respect the hierarchical relation established in L Lami, C Hirche, G Adesso, and A Winter, (2016 Phys. Rev. Lett. 117, 220 502).

Temperature gradient and asymmetric steady state correlations in dissipatively coupled cascaded optomechanical systems

“…We then characterise the correlations established between the mirrors in terms of mutual information and quantum discord, the latter being the best quantifier when one is interested in asymmetries between the two mirrors. Asymmetrical correlations like quantum discord and EPR steering had been investigated in other optomechanical setup [39][40][41][42]. We show that asymmetric non-zero correlations persists even in the steady state.…”

Enhanced the Bi-(Tri-)partite entanglement between three magnons in a cavity magnomechanics system

“…when the magnon excitation numbers satisfy ⟨m † j m j ⟩ << 2N t s = 5N t [24]. According to references [24,26,30], in our simulation, we used YIG spheres with a diameter of 250 µm, containing N t ≃ 3.5 × 10 16 [7,52], where the value of the Kerr coefficient K is determined by the volume of the YIG sphere and is inversely proportional to it. For a YIG sphere with a diameter of 250 µm [24], the Kerr coefficient K is estimated to be approximately 2π × 6.4 × 10 −9 Hz [24].…”

“…In particular, the cavity magnomechanical (CMM) system [8] consists of an MW cavity and a YIG sphere where the magnon mode in the YIG sphere couple simultaneously to the MW cavity and phonon modes through the magnetic dipole interaction and magnetostrictive force (which plays the role of the radiation pressure in optomechanics (OM) systems), respectively. Compared to the OM systems [13][14][15][16][17][18][19], the CMM systems benefit from more flexibility and lower loss, which offers a potential vision for implementing quantum information theory and macroscopic quantum effects. Among these effects, quantum entanglement is a primary physical resource for quantum information processing.…”

Perturbation theoretical approach to determine optomechanical entanglement in mirror-field systems

“…movable mirrors and two or more than two fields has been examined [10][11][12][13][14][15]. The presence of external periodic modulators [16,17] and time-dependent coupling functions [18], optical parametric amplifiers [19,20], a Kerr medium [7], Coulomb interaction between two movable mirrors [21,22], or a quantum dot located on the moving micro-mechanical part [23] have been taken into consideration.…”

“…The presence of external periodic modulators [16,17] and time-dependent coupling functions [18], optical parametric amplifiers [19,20], a Kerr medium [7], Coulomb interaction between two movable mirrors [21,22], or a quantum dot located on the moving micro-mechanical part [23] have been taken into consideration. However, the majority of theoretical studies in this field are purely computational (e.g., [6,9,12,13,15,[19][20][21]23]). Studies producing analytical results have been conducted as well but are outnumbered by the computational studies.…”