• Atomic Physics Faculty
  • William Happer
  • Yuan-Yu Jau
  • Michael Romalis
• Biophysics Theory and Experiment
• Condensed Matter Experiment
• Condensed Matter Theory
• Cosmology Experiment
• Cosmology Theory
• High Energy Experiment
• High Energy Theory
• Mathematical Physics
• Particle and Nuclear Astrophysics

• Quantitative and Computational Biology
• Cosmology at Princeton
• Lewis-Sigler Institute
• Princeton Center for Theoretical Science
• Princeton Institute for the Science
  and Technology of Materials

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. Romalis Group Homepage

S e l e c t e d   P u b l i c a t i o n s:

M.P. Ledbetter and M. V. Romalis, Non-linear effects due to dipolar interactions in hyperpolarized liquid 129Xe, Phys. Rev. Lett. 89 287601 (2002). T.W. Kornack and M.V. Romalis, Dynamics of two overlapping spin ensembles interacting by spin exchange, Phys. Rev. Lett. 89, 253002 (2002). J. C. Allred, R. N. Lyman, T. W. Kornack, and M. V. Romalis, High-sensitivity atomic magnetometer unaffected by spin-exchange relaxation, Phys. Rev. Lett. 89, 130801 (2002). lM. V. Romalis and M. P. Ledbetter, Transverse Spin Relaxation in Liquid 129Xe in the presence of Large Dipolar Fields, Phys. Rev. Lett. 87, 67601 (2001). l M. V. Romalis, W. C. Griffith, J.P. Jacobs, and E.N. Fortson, A New Limit on the Permanent Electric Dipole Moment of 199 Hg, Phys. Rev. Lett. 86, 2505 (2001). l D. M. Haber and M.V. Romalis, Measurement of the Scalar Stark Shift of the 61S0->63P1 Transiton in Mercury, Phys. Rev. A 63, 013402 (2000). l M.V. Romalis, Narrowing of High Power Diode Laser Arrays using Reflection Feedback from an Etalon, Appl. Phys. Lett. 77, 1080, (2000). l M. V. Romalis and E. N. Fortson, Zeeman Frequency Shifts in an Optical Dipole Trap used to Search for an Electric Dipole Moment, Phys. Rev. A 59, 4547 (1999). l M. V. Romalis and W. Happer, Inhomogeneously Broadened Spin Masers, Phys. Rev. A 60, 1385 (1999). l M. V. Romalis and G. D. Cates, Accurate 3He polarimetry using the Rb Zeeman frequency shift due to the Rb-3He spin-exchange collisions, Phys. Rev. A 58, 3004 (1998).