Ken Brown Assistant Professor Office: MSE G025 Phone: 404-385-3124 Fax: 404-894-7452 Research Group Web Page E-mail Ken Brown

B.S., University of Puget Sound, 1998; Ph.D., University of California, Berkeley, 2003; Postdoctoral fellowship, Massachusetts Institute of Technology, 2003-2006

Barry M. Goldwater Scholar, 1997; Kavli Institute for Theoretical Physics, Graduate Fellow, 2001; John and Fannie Hertz Fellow, 1998-2003

Research Interests

Quantum information is an exciting new field that employs quantum mechanical systems to solve problems in computation and communication. The Brown Group uses the experimental and theoretical techniques of quantum information to address challenges in physical chemistry. The basis of our experimental work is a collection of laser cooled ions trapped in a quadrupole ion trap. The theoretical work focuses on understanding the boundary between classical and quantum algorithms for calculating material properties.

Quantum Simulations of Molecules and Materials:

Many materials exhibit magnetic frustration and have low temperature phase diagrams that are often dominated by quantum effects. The Brown Group will examine these quantum effects by building a quantum simulator composed of trapped atomic ions. A quantum simulator will be exponentially more efficient than a classical simulation, making it possible to rapidly calculate the quantum mechanical properties of magnetic materials, superconductors, and molecules.

Cold Molecular Ions:

The reaction dynamics of molecules at millikelvin temperatures exhibit interesting quantum mechanical effects that are typically hidden by thermal averaging. However, preparing molecules at millikelvin temperatures and then accurately measuring reaction products has been a long-standing challenge for physical chemists. The Brown Group is developing a technique that uses atomic ions to cool and measure molecular ions. This technique will allow for the detection of weak molecular transitions by atomic fluorescence which will be useful for fundamental studies of chemical reactions.

Recent Publications

"Loading and characterization of a printed-circuit-board atomic ion trap," K.R. Brown, R.J. Clark, J. Labaziewicz, P. Richerme, D. R. Leibrandt, and I.L. Chuang, Phys.Rev. A, 2007, 75, 015401.

"Limitations of quantum simulation examined by simulating a pairing Hamiltonian using nuclear magnetic resonance", K. R. Brown, R. J. Clark, and I. L. Chuang, Phys. Rev. Lett., 2006, 97, 050504.

"Experimental investigation of planar ion traps," C. E. Pearson, D. R. Leibrandt, W. S. Bakr, W. J. Mallard, K. R. Brown, and I. L. Chuang, Phys. Rev. A, 2006, 73, 032307.

"Bose-Einstein condensation in a mm-scale Ioffe-Pritchard trap," K. L. Moore, T. P. Purdy, K. W. Murch, K. R. Brown, K. Dani, S. Gupta, and D. M. Stamper-Kurn, Applied Physics B, 2006, 82, 533-538.

"Full protection of superconducting qubit systems from coupling errors," M. J. Storcz, J. Vala, K. R. Brown, J. Kempe, F. K. Wilhelm, and K. B. Whaley, Phys. Rev. B, 2005, 72, 065411.

"Bounds on the entanglability of thermal states in liquid-state nuclear magnetic resonance," T. M. Yu, K. R. Brown, and I. L. Chuang, Phys. Rev. A, 2005, 71, 032341.

"Arbitrarily accurate composite pulses," K. R. Brown, A. M. Harrow, and I. L. Chuang, Phys. Rev. A, 2004, 70, 052318.