Macroscopic quantum mechanics: theory and experimental concepts of optomechanics

Abstract

Abstract. Rapid experimental progress has recently allowed the use of light to prepare macroscopic mechanical objects into nearly pure quantum states. This research field of quantum optomechanics opens new doors toward testing quantum mechanics, and possibly other laws of physics, in new regimes. In the first part of this paper, I will review a set of techniques of quantum measurement theory that are often used to analyze quantum optomechanical systems. Some of these techniques were originally designed to analyze how a classical driving force passes through a quantum system, and can eventually be detected with optimal signal-to-noise ratio -while others focus more on the quantum state evolution of a mechanical object under continuous monitoring. In the second part of this paper, I will review a set of experimental concepts that will demonstrate quantum mechanical behavior of macroscopic objects -quantum entanglement, quantum teleportation, and the quantum Zeno effect. Taking the interplay between gravity and quantum mechanics as an example, I will review a set of speculations on how quantum mechanics can be modified for macroscopic objects, and how these speculations -and their generalizations -might be tested by optomechanics.

Measurable signatures of quantum mechanics in a classical spacetime

“…whereĤ OM is the standard optomechanics Hamiltonian for our system [3]. We have ignored corrections due to light's gravity because we are operating in the Newtonian regime, where mass dominates the generation of the gravitational field.Ĥ generates the following linearized state-dependent Heisenberg equations (with the dynamics of the cavity field adiabatically eliminated, and the "H" subscript omitted):…”

“…2 of Ref. [3] for details). The quantity α characterizes the optomechanical coupling, and depends on the pumping power I in and the input-mirror power transmissivity T of the Fabry-Perot cavity:…”

Room-Temperature Steady-State Entanglement in a Four-Mode Optomechanical System

“…Macroscopic entanglement is a research field full of curiosity, and quantum optomechanical system is now considered to be useful for its investigation [7][8][9][10][11][12][13][14]. Generally speaking, the degree of entanglement is usually small (logarithmic negativity E N < 0.7) near the zero temperature.…”

A technique for continuous measurement of the quality factor of mechanical oscillators

“…4,5 Thus, researchers in these fields extensively studied the quality factor of various materials used in these experiments. [5][6][7][8][9][10][11] The related concept of decoherence in quantum mechanical systems also drives researchers of hybrid quantum systems, 12 macroscopic quantum mechanics, 13 cavity opto-mechanics, 14 and superfluid opto-mechanics 15 to design and explore systems with high quality factors.…”