Date:
Tue, 12/11/201312:00-13:30
Location:
Danciger B buildilng, Seminar room
"Optical trapping and cooling of glass microspheres":
In this talk I will review our recent experiments on trapping of glass microspheres in liquid, gas, and vacuum. This work was motivated, in part, by a 1907 paper by Albert Einstein where he considered Brownian motion on short time scales. He predicted that there should be a regime of ballistic motion, unlike random diffusion at longer times. Einstein concluded that this "instantaneous velocity" would be impossible to measure in practice, a prediction that held true for over 100 years. Using the ultra-high sensitivity of our system, we have now measured the instantaneous velocity of a Brownian particle in a gas and in liquids. This work opens the door to the study of statistical mechanics of small systems, non-equilibrium dynamics, and the arrow of time in a liquid.
An optically trapped particle in vacuum is an ideal system for investigating quantum effects in a mechanical system, due to its near-perfect isolation from the thermal environment. We have implemented feedback cooling to control the motion of a trapped microsphere in vacuum. We are able to reduce the center-of-mass temperature of the bead from 300K to 2 mK with this method. We are investigating optimal approaches toward cooling of the bead to the quantum ground state, and the preparation of superposition states of the bead.
In this talk I will review our recent experiments on trapping of glass microspheres in liquid, gas, and vacuum. This work was motivated, in part, by a 1907 paper by Albert Einstein where he considered Brownian motion on short time scales. He predicted that there should be a regime of ballistic motion, unlike random diffusion at longer times. Einstein concluded that this "instantaneous velocity" would be impossible to measure in practice, a prediction that held true for over 100 years. Using the ultra-high sensitivity of our system, we have now measured the instantaneous velocity of a Brownian particle in a gas and in liquids. This work opens the door to the study of statistical mechanics of small systems, non-equilibrium dynamics, and the arrow of time in a liquid.
An optically trapped particle in vacuum is an ideal system for investigating quantum effects in a mechanical system, due to its near-perfect isolation from the thermal environment. We have implemented feedback cooling to control the motion of a trapped microsphere in vacuum. We are able to reduce the center-of-mass temperature of the bead from 300K to 2 mK with this method. We are investigating optimal approaches toward cooling of the bead to the quantum ground state, and the preparation of superposition states of the bead.