Myungshik Kim

Classical mechanics and electrodynamics are enough for the description of the world we experience daily. However, with the improvement of technology, we are approaching the limit where quantum mechanics must come in for explanations of novel phenomena. A typical example would be an optomechanical cavity. The cavity is formed of two mirrors, with one of them movable, acting as a mechanical oscillator. If the system is fabricated with state-of-art technologies, classical inputs to the system (e.g. laser driving of the cavity) will result in nonclassical properties, for example, the generation of superposition states. They provide valuable resources for both applications and fundamental studies of physics.

 However, how to define quantumness is a nontrivial question. We need to make sure there is no classical counterpart. Due to the existence of a noisy environment, quantum states quickly lose their nonclassical signatures. Careful analysis must be done to separate quantum features.

 This project starts from examining physical systems to see whether some usually believed quantum signatures are indeed quantum. For example, the optomechanical system mentioned above will be checked. If classical descriptions can account for the quantities we are interested in, great calculation efforts can be saved. This may lead to the improvement towards analysis based on more realistic conditions that go beyond current approximations, such as the case where pulse serves as an input to an optomechanical cavity. Those properties that are proved to be really quantum, on the other hand, will shed light on the fundamental studies, for example, which quantum nature leads to which observable effect. It may act as a guide towards experimental test of quantum mechanics.