Talk #47, 5/20/09

Quantum Mechanics of Macroscopic Objects

Yanbei Chen

Quantum Mechanics of Macroscopic Objects

Quantum mechanics was invented to describe the microscopic world. Over the past century, it has allowed us to understand behaviors of electrons in atoms, chemical compounds, solids, as well as underlying constituents of the atomic nucleus — while at the same time revolutionizing technology, making possible things like personal computers, nuclear energy, advanced materials, etc.Laws of quantum mechanics are probabilistic in nature, and impose fundamental uncertainties when one tries to describe them in classical terms. As an example, the Heisenberg Uncertainty Principle dictates that position and speed of an object cannot be simultaneously specified with infinite accuracy. This Principle plays an important role in assuring that the atomic nucleus (with positive charge) and the electrons encircling it (with negative charge) do not collapse into each other.In recent years, the need to improve precision measurement devices, in particular gravitational-wave detectors, has required us to apply the Heisenberg Uncertainty Principle to macroscopic objects — even human- sized objects (e.g., mirrors that weigh as much as 40 kg). The speaker will discuss how to circumvent measurement noises imposed by the Heisenberg Uncertainty Principle, and, on the other hand, how one can use these devices to demonstrate that macroscopic objects do behave quantum mechanically.


The following is a link to the full presentation (pdf format).