# 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.

## Appointments and Affiliations

- Professor of Physics

## Contact Information

**Office Location:**291 Physics Bldg, Durham, NC 27708**Office Phone:**(919) 660-2598**Email Address:**harold.baranger@duke.edu**Websites:**

## Education

- Ph.D. Cornell University, 1986
- M.S. Cornell University, 1983

## Awards, Honors, and Distinctions

- Fellow. American Physical Society. 2007

## Courses Taught

- PHYSICS 509: Quantum Nanophysics
- PHYSICS 516: Quantum Materials: Introduction to Solid State Physics
- PHYSICS 607: Introduction to Condensed Matter Physics
- PHYSICS 764: Quantum Mechanics
- PHYSICS 810: Advanced Solid-State Physics

## Representative Publications

- Calajó, G; Fang, Y-LL; Baranger, HU; Ciccarello, F,
*Exciting a Bound State in the Continuum through Multiphoton Scattering Plus Delayed Quantum Feedback.*, Physical Review Letters, vol 122 no. 7 (2019) [10.1103/physrevlett.122.073601] [abs]. - Gheeraert, N; Zhang, XHH; Sépulcre, T; Bera, S; Roch, N; Baranger, HU; Florens, S,
*Particle production in ultrastrong-coupling waveguide QED*, Physical Review A, vol 98 no. 4 (2018) [10.1103/PhysRevA.98.043816] [abs]. - Fang, YLL; Ciccarello, F; Baranger, HU,
*Non-Markovian dynamics of a qubit due to single-photon scattering in a waveguide*, New Journal of Physics, vol 20 no. 4 (2018) [10.1088/1367-2630/aaba5d] [abs]. - Zhang, XHH; Baranger, HU,
*Quantum interference and complex photon statistics in waveguide QED*, Physical Review A, vol 97 no. 2 (2018) [10.1103/PhysRevA.97.023813] [abs]. - Zhang, XHH; Baranger, HU,
*Photon Statistics in a Waveguide: Beyond Bunching and Antibunching*, arXiv, vol 1710 (2017) [abs].