Research

The Laboratory for Emerging Technologies seeks to understand unconventional phenomena in quantum, optical, biological, and material systems; and to see how these can be engineered to develop new technologies and devices. We currently focus on:

Quantum Phase Transitions and Holographic Superconductivity

Quantum phase transitions are transitions between states of matter in a system, which arise due to changes in the parameters of a Hamiltonian totally independent of temperature. These are driven by quantum fluctuations, and have been realized in phenomena ranging from Wigner crystallization and nematic phases in electron gases to holographic superconductivity. Using experimental techniques (in particular high-resolution transmission electron microscopy) and theoretically (using Fermi liquid theory and techniques from AdS/CFT), we examine how quantum phase transitions may be engineered and applied to physical devices.

Publications:

  • C. Yang et al., Science 366, 1505 (2019): “Intermediate Bosonic Metallic State in the Superconductor-Insulator Transition”.
  • X. Zhang et al., Phys. Rev. Lett. 122, 157002 (2019): “Quasiparticle Screening Near a Bosonic Superconductor-Insulator Transition Revealed by Magnetic Impurity Doping”.
  • H. Q. Nguyen et al., Scientific Reports 6, 38166 (2016): “Driving a Superconductor to Insulator Transition with Random Gauge Fields”.
  • H. Q. Nguyen et al., Phys. Rev. B 92, 140501(R) (2015): “Disorder Influences the Quantum Critical Transport at a Superconductor-to-Insulator Transition”.
  • S. M. Hollen et al., Phys. Rev. B 90, 140506(R) (2014): “Fate of the Bose Insulator in the Limit of Strong Localization and Low Cooper-pair Density in Ultrathin Films”.
  • S. M. Hollen et al., Phys. Rev. B 87, 054512 (2013): “Collapse of the Cooper Pair Phase Coherence Length at a Superconductor-to-Insulator Transition”.
  • S. M. Hollen et al., Phys. Rev. B 84, 064528 (2011): “Cooper-Pair Insulator Phase in Superconducting Amorphous Bi Films Induced by Nanometer-Scale Thickness Variations”.
  • H. Q. Nguyen et al., Phys. Rev. Lett. 103, 157001 (2009): “Observation of Giant Positive Magnetoresistance in a Cooper Pair Insulator”.
  • M. D. Stewart Jr. et al., Phys. Rev. B 77, 140501(R) (2008): “Magnetic-Field-Tuned Superconductor-to-Insulator Transitions in Amorphous Bi Films with Nanoscale Hexagonal Arrays of Holes”.
  • M. D. Stewart Jr. et al., Science 318, 1273 (2007): “Superconducting Pair Correlations in an Amorphous Insulating Nanohoneycomb Film”.
  • M. D. Stewart Jr. et al., Phys. Rev. B. 73, 092509 (2006): “Magnetic-Flux Periodic Response of Nanoperforated Ultrathin Superconducting Films”.
  • U. Welp et al., Phys. Rev. B 66, 212507 (2002): “Superconducting Transition and Vortex Pinning in Nb Films Patterned with Nanoscale Hole Arrays”.

Nonlinear and Quantum Optical Phenomena

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Quantum Geometry and Quantum Thermodynamics in Computing and Molecules

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