Smitha Vishveshwara

Assistant Professor

Ph.D., Physics, Univ. of California, Santa Barbara, 2002

Professor Smitha Vishveshwara received her bachelor's degree in physics magna cum laude from Cornell University in 1996, and her Ph.D in theoretical physics from the University of California, Santa Barbara, in 2002. She served as a postdoctoral research associate with Paul Goldbart and Tony Leggett from 2002 to 2005, working on tunneling and fractional statistics in quantum Hall systems, Aharonov-Bohm effects in carbon nanotubes (as reported in Science), and critical dynamics in charged superconductors. She joined the department as an assistant professor in August 2005.

Professor Vishveshwara's research interests span a broad range of topics in theoretical condensed matter physics, and she maintains strong collaborative ties with experimentalists. Over the next few years, she plans to extend ongoing projects, to expand her research into problems involving ultracold atoms trapped in optical lattices, electronic properties of single-walled nanotubes, and exotic features of quantum Hall states.

Other Activities

My researches explores a diverse set of issues in condensed matter physics, and in particular, in strongly correlated states of matter at scales where quantum phenomena play a role. Topics currently being studied are carbon nanotubes; quantum dots; cold atomic gases and optical lattices; fractional quantum Hall states and anyons; critical phenomena.

Co-existence of quantum phases in optical lattices
Interacting bosons confined to a pure lattice can exhibit either Mott insulating behavior, where constituent particles are pinned to lattice sites, or superfluid order, where particles are delocalized over sites. Under certain conditions, trapped bosons in optical lattices can display co-existence of the two phases. Professor Vishveshwara's current research involves various aspects of these co-existent phases, such as collective behavior, dynamics, and critical properties. Her collaborative efforts have explored the conditions for realizing multiple Mott insulating phases in optical lattices and their signatures in spectroscopic measurements.

Probing hallmarks of fractional quantum Hall systems via tunneling
The natural quasiparticle excitations of the fractional quantum Hall (FQH) system are bizarre objects whose identity is "orthogonal" to the constituent electrons. In particular, these particles are predicted to have fractional charge and fractional statistics. Professor Vishveshwara has proposed a Hall bar setup for making measurements analogous to those of the Hanbury Brown-Twiss experiment, which revealed the bosonic statistics of photons some decades ago. With her collaborators, she has shown that appropriate correlations of quasiparicle tunneling current exhibit signatures of both fractional statistics and fractional charge. Professor Vishveshwara has also explored the possibility of Cooper-pair tunneling from a superconducting lead into singlet FQH states. Such a setup could enable filtering and locking into specific FQH states. Furthermore, under certain conditions, it could enable Cooper pairs to split into constituent electrons that tunnel into two edge states.

View Professor Vishveshwara's lecture, " Uncovering Fractional Statistics Via a Hanbury Brown Twiss Setup," presented at the Kavli Institute of Theoretical Physics, June 10, 2003.

Honors and awards:

• Center for Advanced Study Associate, 2009/10
• National Science Foundation CAREER Award, 2007

Selected Publications:

• S. Vishveshwara and C. Lannert. Josephson physics mediated by the Mott insulating phase. Phys. Rev. A 78, 053620 (2008)
• Vishveshwara, S., Stone, M., and Sen, D. Correlators and fractional statistics in the quantum Hall bulk. Physical Review Letters, 99:19, 190401 (Nov. 2007)
• E.-A. Kim, M. Lawler, S. Vishveshwara, and E. H. Fradkin. Signatures of fractional statistics in noise experiments in quantum Hall fluids. Phys. Rev. Lett. 95, 176402-1-4 (2005).
• B. DeMarco, S. Lannert, S. Vishveshwara, and T.-C. Wei. Structure and stability of Mott-insulator shells of bosons trapped in an optical lattice. Phys. Rev. A 71, 063601-1-11 (2005).
• T.-C. Wei, D. Das, S. Mukhopadyay, S. Vishveshwara, and P. M. Goldbart. Global entanglement and quantum criticality in spin chains. Phys. Rev. A 71, 060305(R)-1-4 (2005).
• U. C. Coskun, T. C. Wei, S. Vishveshwara, P. M. Goldbart, and A. Bezryadin. h/e magnetic flux modulation of the energy gap in nanotube quantum dots. Science 304, 1132-1134 (2004). WP NOTES: italic h/e
• E.-A. Kim, S. Vishveshwara, and E. H. Fradkin. Cooper-pair tunneling in junctions of singlet quantum Hall states and superconductors. Phys. Rev. Lett. 93, 266803-1-4 (2004).
• C. Lannert, S. Vishveshwara, and M. P. A. Fisher. Critical dynamics of superconductors in the charged regime. Phys. Rev. Lett. 92, 097004-1-4 (2004).
• S. Vishveshwara. Revisiting the Hanbury Brown-Twiss setup for fractional statistics. Phys. Rev. Lett. 91, 196803-1-4 (2003).