Harold U. Baranger
Professor of Physics
The broad focus of Prof. Baranger's group is quantum open systems at the nanoscale, particularly the generation of correlation between particles in such systems. Fundamental interest in nanophysics-- the physics of small, nanometer scale, bits of solid-- stems from the ability to control and probe systems on length scales larger than atoms but small enough that the averaging inherent in bulk properties has not yet occurred. Using this ability, entirely unanticipated phenomena can be uncovered on the one hand, and the microscopic basis of bulk phenomena can be probed on the other. Additional interest comes from the many links between nanophysics and nanotechnology. Within this thematic area, our work ranges from projects trying to nail down realistic behavior in well-characterized systems, to more speculative projects reaching beyond regimes investigated experimentally to date.
Correlations between particles are a central issue in many areas of condensed matter physics, from emergent many-body phenomena in complex materials, to strong matter-light interactions in quantum information contexts, to transport properties of single molecules. Such correlations, for either electrons or bosons (photons, plasmons, phonons,…), underlie key phenomena in nanostructures. Using the exquisite control of nanostructures now possible, experimentalists will be able to engineer correlations in nanosystems in the near future. Of particular interest are cases in which one can tune the competition between different types of correlation, or in which correlation can be tunably enhanced or suppressed by other effects (such as confinement or interference), potentially causing a quantum phase transition-- a sudden, qualitative change in the correlations in the system.
My recent work has addressed correlations in both electronic systems (quantum wires and dots) and photonic systems (photon waveguides). We have focused on 3 different systems: (1) qubits coupled to a photonic waveguide, (2) quantum dots in a dissipative environment, and (3) low-density electron gas in a quantum wire. The methods used are both analytical and numerical, and are closely linked to experiments.
Matveev, K. A., et al. “Theory of Coulomb blockade of tunneling through a double quantum dot.” Surface Science, vol. 361–362, July 1996, pp. 623–26. Scopus, doi:10.1016/0039-6028(96)00484-0. Full Text
Chang, A. M., et al. “Non-Gaussian distribution of Coulomb blockade peak heights in quantum dots.” Physical Review Letters, vol. 76, no. 10, Mar. 1996, pp. 1695–98. Epmc, doi:10.1103/physrevlett.76.1695. Full Text
Baranger, H. U., and P. A. Mello. “Short paths and information theory in quantum chaotic scattering: Transport through quantum dots.” Europhysics Letters, vol. 33, no. 6, Feb. 1996, pp. 465–70. Scopus, doi:10.1209/epl/i1996-00364-5. Full Text
Matveev, K. A., et al. “Tunneling spectroscopy of quantum charge fluctuations in the Coulomb blockade.” Physical Review. B, Condensed Matter, vol. 53, no. 3, Jan. 1996, pp. 1034–37. Epmc, doi:10.1103/physrevb.53.1034. Full Text
Sumetskii, M. I., and H. U. Baranger. “Change in sign of the photocurrent in a coherent asymmetric superlattice.” Applied Physics Letters, vol. 67, Dec. 1995, p. 3560. Scopus, doi:10.1063/1.114921. Full Text
Mello, P. A., and H. U. Baranger. “Electronic transport through ballistic chaotic cavities: an information theoretic approach.” Physica A: Statistical Mechanics and Its Applications, vol. 220, no. 1–2, Oct. 1995, pp. 15–23. Scopus, doi:10.1016/0378-4371(95)00121-M. Full Text
Baranger, H. U. “Quantum transport and chaos in semiconductor microstructures.” Physica D: Nonlinear Phenomena, vol. 83, no. 1–3, May 1995, pp. 30–45. Scopus, doi:10.1016/0167-2789(94)00248-O. Full Text
Aleiner, I. L., et al. “Tunneling into a Two-Dimensional Electron Liquid in a Weak Magnetic Field.” Physical Review Letters, vol. 74, no. 17, Apr. 1995, pp. 3435–38. Epmc, doi:10.1103/physrevlett.74.3435. Full Text
Baranger, H. U., and P. A. Mello. “Effect of phase breaking on quantum transport through chaotic cavities.” Physical Review. B, Condensed Matter, vol. 51, no. 7, Feb. 1995, pp. 4703–06. Epmc, doi:10.1103/physrevb.51.4703. Full Text
Sumetskii, M. I., and H. U. Baranger. “Studying the insulator-conductor interface with a scanning tunneling microscope.” Applied Physics Letters, Jan. 1995, p. 1352. Scopus, doi:10.1063/1.113198. Full Text