Research: Biophysics theory and experiment
230 Jadwin Hall
I am interested in applications of atomic physics techniques to fundamental questions about the workings of the Universe. We are presently conducting two experiments to test symmetries of physical laws. In one experiment we are searching for a permanent electric dipole moment of 129Xe atoms, which can only exist if time-reversal symmetry, as well as CP symmetry, are violated. While CP symmetry is violated at a small level in the Standard Model, this violation is insufficient to explain the asymmetry between matter and anti-matter in the Universe. Our experiment is particularly sensitive to new sources of CP violation beyond the Standard Model. In another experiment we are searching for evidence of violation of Lorentz symmetry and CPT symmetry. While these symmetries are on a firm ground within a conventional field theory, they can be violated in more general theories including quantum gravity. Thus, CPT and Lorentz symmetry violations are some of the very few experimentally accessible signatures of quantum gravity effects.
Our experiments are typically performed by a small group of people and use a variety of experimental techniques and devices, such as optical pumping, NMR, high-Tc SQUID magnetometers, single frequency and high power diode lasers, multi-layer magnetic shields, ultra-low noise electronics, etc. Substantial effort is also devoted to detailed understanding and modeling of various systematic effects. We are also exploring practical applications of the precision atomic physics techniques. Recently we developed a very sensitive atomic magnetometer that can surpass even low-temperature SQUID detectors in magnetic field sensitivity. In collaboration with Princeton Center for Brain, Mind and Behavior we are developing its applications for imaging of the magnetic fields produced by the brain.
- Dong Sheng, Shuguang Li, Nezih Dural, and Mike Romalis have published a paper on Subfemtotesla Scalar Atomic Magnetometry Using Multipass Cells. in Physical Review Letters, 110, 160802 (2013) [Copyright APS].
- Junhui Shi, Suvi Ikäläinen, Juha Vaara, and Mike Romalis have published a paper on Observation of Optical Chemical Shift by Precision Nuclear Spin Optical Rotation Measurements and Calculations. in The Journal of Physical Chemistry Letters 2013, 4 (3), pp 437-441 [Copyright ACS].
- Micah Ledbetter, Giacomo Saielli, Alessandro Bagno, Nhan Tran, and Mike Romalis have published a paper on Observation of scalar nuclear spin?~@~Sspin coupling in van der Waals complexes. Proceedings of the National Academy of Sciences of the United States of America 109(31) 12393 (2012) [Copyright PNAS].
- G. Vasilakis. "Precision Measurements of Spin Interactions with High Density Atomic Vapors." Dissertation, Princeton University (2011).
- J. M. Brown. "A New Limit on Lorentz- and CPT-Violating Neutron Spin Interactions Using a K-3He Comagnetometer." Dissertation, Princeton University (2011).
- Shuguang Li, P. Vachaspati, Dong Sheng, Nezih Dural, and Mike Romalis have published a paper on Optical rotation in excess of 100 rad generated by Rb vapor in a multipass cell. in Physical Review A [Copyright APS].
- M. Smiciklas, Justin Brown, L. Cheuk, S. Smullin and Mike Romalis have published a paper on New Test of Local Lorentz Invariance Using a 21Ne-Rb-K Comagnetometer in Physical Review Letters 107, 171604 (2011) [Copyright APS].
- Giorgos Vasilakis, Vishal Shah, and Mike Romalis have published a paper on Stroboscopic Backaction Evasion in a Dense Alkali-Metal Vapor in Physical Review Letters 106, 143601 (2011) [Copyright APS].
- Mike Romalis has published a paper on Hybrid Optical Pumping of Optically Dense Alkali-Metal Vapor without Quenching Gas in Physical Review Letters 105, 243001 (2010) [Copyright APS].
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