A. Shearrow

Hardware implementation of quantum stabilizers in superconducting circuits

  1. K. Dodge,
  2. Y. Liu,
  3. A. R. Klots,
  4. B. Cole,
  5. A. Shearrow,
  6. M. Senatore,
  7. S. Zhu,
  8. L.B. Ioffe,
  9. R. McDermott,
  10. and B. L. T. Plourde
Stabilizer operations are at the heart of quantum error correction and are typically implemented in software-controlled entangling gates and measurements of groups of qubits. Alternatively,
qubits can be designed so that the Hamiltonian corresponds directly to a stabilizer for protecting quantum information. We demonstrate such a hardware implementation of stabilizers in a superconducting circuit composed of chains of π-periodic Josephson elements. With local on-chip flux- and charge-biasing, we observe a softening of the energy band dispersion with respect to flux that is exponential in the number of frustrated plaquette elements, in close agreement with our numerical modeling.
arxiv pdf

Atomic layer deposition of titanium nitride for quantum circuits

  1. A. Shearrow,
  2. G. Koolstra,
  3. S. J. Whiteley,
  4. N. Earnest,
  5. P. S. Barry,
  6. F. J. Heremans,
  7. D. D. Awschalom,
  8. E. Shirokoff,
  9. and D.I. Schuster
Superconducting thin films with high intrinsic kinetic inductance are of great importance for photon detectors, achieving strong coupling in hybrid systems, and protected qubits. We
report on the performance of titanium nitride resonators, patterned on thin films (9-110 nm) grown by atomic layer deposition, with sheet inductances of up to 234 pH/square. For films thicker than 14 nm, quality factors measured in the quantum regime range from 0.4 to 1.0 million and are likely limited by dielectric two-level systems. Additionally, we show characteristic impedances up to 28 kOhm, with no significant degradation of the internal quality factor as the impedance increases. These high impedances correspond to an increased single photon coupling strength of 24 times compared to a 50 Ohm resonator, transformative for hybrid quantum systems and quantum sensing.
arxiv pdf