Sarah Muschinske

Flat-band (de)localization emulated with a superconducting qubit array

  1. Ilan T. Rosen,
  2. Sarah Muschinske,
  3. Cora N. Barrett,
  4. David A. Rower,
  5. Rabindra Das,
  6. David K. Kim,
  7. Bethany M. Niedzielski,
  8. Meghan Schuldt,
  9. Kyle Serniak,
  10. Mollie E. Schwartz,
  11. Jonilyn L. Yoder,
  12. Jeffrey A. Grover,
  13. and William D. Oliver
Arrays of coupled superconducting qubits are analog quantum simulators able to emulate a wide range of tight-binding models in parameter regimes that are difficult to access or adjust
in natural materials. In this work, we use a superconducting qubit array to emulate a tight-binding model on the rhombic lattice, which features flat bands. Enabled by broad adjustability of the dispersion of the energy bands and of on-site disorder, we examine regimes where flat-band localization and Anderson localization compete. We observe disorder-induced localization for dispersive bands and disorder-induced delocalization for flat bands. Remarkably, we find a sudden transition between the two regimes and, in its vicinity, the semblance of quantum critical scaling.
arxiv pdf

Implementing a synthetic magnetic vector potential in a 2D superconducting qubit array

  1. Ilan T. Rosen,
  2. Sarah Muschinske,
  3. Cora N. Barrett,
  4. Arkya Chatterjee,
  5. Max Hays,
  6. Michael DeMarco,
  7. Amir Karamlou,
  8. David Rower,
  9. Rabindra Das,
  10. David K. Kim,
  11. Bethany M. Niedzielski,
  12. Meghan Schuldt,
  13. Kyle Serniak,
  14. Mollie E. Schwartz,
  15. Jonilyn L. Yoder,
  16. Jeffrey A. Grover,
  17. and William D. Oliver
Superconducting quantum processors are a compelling platform for analog quantum simulation due to the precision control, fast operation, and site-resolved readout inherent to the hardware.
Arrays of coupled superconducting qubits natively emulate the dynamics of interacting particles according to the Bose-Hubbard model. However, many interesting condensed-matter phenomena emerge only in the presence of electromagnetic fields. Here, we emulate the dynamics of charged particles in an electromagnetic field using a superconducting quantum simulator. We realize a broadly adjustable synthetic magnetic vector potential by applying continuous modulation tones to all qubits. We verify that the synthetic vector potential obeys requisite properties of electromagnetism: a spatially-varying vector potential breaks time-reversal symmetry and generates a gauge-invariant synthetic magnetic field, and a temporally-varying vector potential produces a synthetic electric field. We demonstrate that the Hall effect–the transverse deflection of a charged particle propagating in an electromagnetic field–exists in the presence of the synthetic electromagnetic field.
arxiv pdf

Quantum transport and localization in 1d and 2d tight-binding lattices

  1. Amir H. Karamlou,
  2. Jochen Braumüller,
  3. Yariv Yanay,
  4. Agustin Di Paolo,
  5. Patrick Harrington,
  6. Bharath Kannan,
  7. David Kim,
  8. Morten Kjaergaard,
  9. Alexander Melville,
  10. Sarah Muschinske,
  11. Bethany Niedzielski,
  12. Antti Vepsäläinen,
  13. Roni Winik,
  14. Jonilyn L. Yoder,
  15. Mollie Schwartz,
  16. Charles Tahan,
  17. Terry P. Orlando,
  18. Simon Gustavsson,
  19. and William D. Oliver
Particle transport and localization phenomena in condensed-matter systems can be modeled using a tight-binding lattice Hamiltonian. The ideal experimental emulation of such a model
utilizes simultaneous, high-fidelity control and readout of each lattice site in a highly coherent quantum system. Here, we experimentally study quantum transport in one-dimensional and two-dimensional tight-binding lattices, emulated by a fully controllable 3×3 array of superconducting qubits. We probe the propagation of entanglement throughout the lattice and extract the degree of localization in the Anderson and Wannier-Stark regimes in the presence of site-tunable disorder strengths and gradients. Our results are in quantitative agreement with numerical simulations and match theoretical predictions based on the tight-binding model. The demonstrated level of experimental control and accuracy in extracting the system observables of interest will enable the exploration of larger, interacting lattices where numerical simulations become intractable.
arxiv pdf