Ge Yang

Electron on solid neon — a new solid-state single-electron qubit platform

  1. Xianjing Zhou,
  2. Gerwin Koolstra,
  3. Xufeng Zhang,
  4. Ge Yang,
  5. Xu Han,
  6. Brennan Dizdar,
  7. Divan Ralu,
  8. Wei Guo,
  9. Kater W. Murch,
  10. David I. Schuster,
  11. and Dafei Jin
The promise of quantum computing has driven a persistent quest for new qubit platforms with long coherence, fast operation, and large scalability. Electrons, ubiquitous elementary particles
of nonzero charge, spin, and mass, have commonly been perceived as paradigmatic local quantum information carriers. Despite superior controllability and configurability, their practical performance as qubits via either motional or spin states depends critically on their material environment. Here we report our experimental realization of a new qubit platform based upon isolated single electrons trapped on an ultraclean solid neon surface in vacuum. By integrating an electron trap in a circuit quantum electrodynamics architecture, we achieve strong coupling between the motional states of a single electron and microwave photons in an on-chip superconducting resonator. Qubit gate operations and dispersive readout are used to measure the energy relaxation time T1 of 15 μs and phase coherence time T2 over 200 ns, indicating that the electron-on-solid-neon qubit already performs near the state of the art as a charge qubit.
arxiv pdf

Coupling an ensemble of electrons on superfluid helium to a superconducting circuit

  1. Ge Yang,
  2. A. Fragner,
  3. G. Koolstra,
  4. L. Ocola,
  5. D.A. Czaplewski,
  6. R. J. Schoelkopf,
  7. and D.I. Schuster
The quantized lateral motional states and the spin states of electrons trapped on the surface of superfluid helium have been proposed as basic building blocks of a scalable quantum
computer. Circuit quantum electrodynamics (cQED) allows strong dipole coupling between electrons and a high-Q superconducting microwave resonator, enabling such sensitive detection and manipulation of electron degrees of freedom. Here we present the first realization of a hybrid circuit in which a large number of electrons are trapped on the surface of superfluid helium inside a coplanar waveguide resonator. The high finesse of the resonator allows us to observe large dispersive shifts that are many times the linewidth and make fast and sensitive measurements on the collective vibrational modes of the electron ensemble, as well as the superfluid helium film underneath. Furthermore, a large ensemble coupling is observed in the dispersive regime during experiment, and it shows excellent agreement with our numeric model. The coupling strength of the ensemble to the cavity is found to be >1 MHz per electron, indicating the feasibility of achieving single electron strong coupling.
arxiv pdf