Centre for Engineered Quantum Systems, University of Queensland, Australia.
Phys Rev Lett. 2011 Nov 18;107(21):213603. doi: 10.1103/PhysRevLett.107.213603. Epub 2011 Nov 15.
Nonlinear forces allow motion of a mechanical oscillator to be squeezed below the zero-point motion. Of existing methods, mechanical parametric amplification is relatively accessible, but previously thought to be limited to 3 dB of squeezing in the steady state. We consider the effect of applying continuous weak measurement and feedback to this system. If the parametric drive is optimally detuned from resonance, correlations between the quadratures of motion allow unlimited steady-state squeezing. Compared to backaction evasion, we demonstrate that the measurement strength, temperature and efficiency requirements for quantum squeezing are significantly relaxed.
非线性力允许机械振荡器的运动被挤压到零点运动以下。在现有的方法中，机械参量放大相对容易实现，但以前认为它在稳态下只能达到 3 dB 的压缩。我们考虑在这个系统中施加连续弱测量和反馈的效果。如果参量驱动与共振最优失谐，运动的正交分量之间的相关性允许无限的稳态压缩。与反作用规避相比，我们证明了量子压缩的测量强度、温度和效率要求显著放宽。
