Strong quadrature squeezing and quantum amplification in a coupled Bose–Einstein condensate—optomechanical cavity based on parametric modulation

Abstract

We consider an optomechanical cavity with a movable end-mirror as a quantum mechanical oscillator (MO) containing an interacting cigar-shaped Bose-Eisenstein condensate (BEC). It is assumed that both the MO and the BEC interact with the radiation pressure of the cavity field in the red-detuned and weak coupling regimes while the two-body atomic collisions frequency of the BEC and the mechanical spring coefficient of the MO are coherently modulated. By analyzing the scattering matrix we find that a frequency-dependent squeezing is induced to the three subsystems only due to the coherent modulations. In the largely different cooperativities regime together with strong modulations, the mechanical mode of the MO and the Bogoliubov mode of the BEC exhibit quadrature squeezing which can surpass the so-called 3dB limit (up to 75 dB) with high robustness to the thermal noises. Surprisingly, in this regime by controlling the system and modulation parameters, a very high degree of squeezing (up to 16 dB) together with high purity of quantum state for the output cavity field is achievable. Furthermore, one can attain simultaneous strong quantum amplification, added-noise suppression, and controllable gain-bandwidth for the complementary quadratures of squeezed ones in the subsystems.

Back-action evading measurement of the collective mode of a Bose–Einstein condensate

“…In this way, for lager values of ω sw the minimum of the onresonance added noise gets lower. On the other hand, in order to show how much the added noise of measurement in the present hybrid system can be decreased below the SQL, in figure (4) we have plotted n min add (0), i.e., equation (36), versus the swave scattering frequency for four different values of the cavity decay rates. It is obviously seen that the minimum of the added noise decreases with the increase of ω sw for any value of κ.…”

“…Furthermore, the problem of parametric instability of the present scheme has been investigated theoretically and experimentally [30,31]. After this proposal, modulated optomechanical systems have attracted a lot of attention [32][33][34][35][36]. It can also be generalized to the back-action evading measurement of the collective quadrature of two mechanical oscillators [37].…”

Force sensing in hybrid Bose-Einstein-condensate optomechanics based on parametric amplification

“…where the optical gain G a , which is defined in the context of the linear amplifiers as the ratio of photons number in the output of the amplifier to that in the input [65], is given by [63] G…”

Homodyne coherent quantum noise cancellation in a hybrid optomechanical force sensor

“…Optomechanical systems (OMSs) have been exploited in different areas of quantum technologies, such as quantum information processing and communication [1][2][3][4], quantum memories [5,6], reversible microwave-to-optics converters [7][8][9][10][11], microwave circulators [12,13], quantum correlations [14][15][16][17][18], quantum squeezing [19,20], as well as in fundamental physics [21][22][23][24][25][26][27][28][29][30]. Also, optomechanical-based sensors have been recognized as optimal candidate for the detection of minuscule forces at the quantum limit [31] such as observation of gravitational waves [32].…”