Jerry Chow - Academia.edu (original) (raw)

Papers by Jerry Chow

Quantum Science and Technology

Quantum science and technology, 2018

We demonstrate a pogo pin package for a superconducting quantum processor specifically designed w... more We demonstrate a pogo pin package for a superconducting quantum processor specifically designed with a nontrivial layout topology (e.g., a center qubit that cannot be accessed from the sides of the chip). Two experiments on two nominally identical superconducting quantum processors in pogo packages, which use commercially available parts and require modest machining tolerances, are performed at low temperature (10 mK) in a dilution refrigerator and both found to behave comparably to processors in standard planar packages with wirebonds where control and readout signals come in from the edges. Single- and two-qubit gate errors are also characterized via randomized benchmarking, exhibiting similar error rates as in standard packages, opening the possibility of integrating pogo pin packaging with extensible qubit architectures.

Physical review letters, Jan 3, 2017

Robust quantum computation requires encoding delicate quantum information into degrees of freedom... more Robust quantum computation requires encoding delicate quantum information into degrees of freedom that are hard for the environment to change. Quantum encodings have been demonstrated in many physical systems by observing and correcting storage errors, but applications require not just storing information; we must accurately compute even with faulty operations. The theory of fault-tolerant quantum computing illuminates a way forward by providing a foundation and collection of techniques for limiting the spread of errors. Here we implement one of the smallest quantum codes in a five-qubit superconducting transmon device and demonstrate fault-tolerant state preparation. We characterize the resulting code words through quantum process tomography and study the free evolution of the logical observables. Our results are consistent with fault-tolerant state preparation in a protected qubit subspace.

Physical review letters, Jan 18, 2016

We present parity measurements on a five-qubit lattice with connectivity amenable to the surface ... more We present parity measurements on a five-qubit lattice with connectivity amenable to the surface code quantum error correction architecture. Using all-microwave controls of superconducting qubits coupled via resonators, we encode the parities of four data qubit states in either the X or the Z basis. Given the connectivity of the lattice, we perform a full characterization of the static Z interactions within the set of five qubits, as well as dynamical Z interactions brought along by single- and two-qubit microwave drives. The parity measurements are significantly improved by modifying the microwave two-qubit gates to dynamically remove nonideal Z errors.

Physical Review Letters, 2016

2016 46th European Solid-State Device Research Conference (ESSDERC), 2016

Bulletin of the American Physical Society, Mar 3, 2014

Aps Meeting Abstracts, Mar 1, 2010

We employ a single channel as a joint readout of highly-entangled two-qubit states in a circuit q... more We employ a single channel as a joint readout of highly-entangled two-qubit states in a circuit quantum electrodynamics architecture. The measurement model for the readout is fully characterized using a set of Rabi experiments demonstrating a large sensitivity to two-qubit correlations. ...

Aps Meeting Abstracts, Mar 1, 2008

In circuit QED, the transmon qubit[1] allows long coherence times and strong coupling. In this re... more In circuit QED, the transmon qubit[1] allows long coherence times and strong coupling. In this regime, tuning the qubit into resonance with the cavity leads to vacuum Rabi splitting[2] with two transmission peaks very well-resolved in frequency (˜300 linewidths apart). At low probe power, these peaks have Lorentzian shape. As the probe power is increased, each Rabi peak is observed to split into two peaks. Approximating the combined qubit and cavity as a two-level system and applying the theory of resonance fluorescence reproduces the main features of this phenomenon. We explore the effects of including additional levels of the transmon and cavity in the detailed theoretical modeling of the experiment. Additionally, we discuss the possibility to observe the Mollow triplet in the fluorescence spectrum. [1] Jens Koch, TM Yu, JM Gambetta, AA Houck, DI Schuster, J Majer, A Blais, MH Devoret, SM Girvin, and RJ Schoelkopf. Phys. Rev. A 76, 042319 (2007) [2] A Wallraff, D Schuster, A Blais, L Frunzio, R-S Huang, J Majer, S Kumar, SM Girvin and RJ Schoelkopf, Nature 431, 162 (2004)

Bulletin of the American Physical Society, Mar 3, 2015

Aps Meeting Abstracts, Mar 1, 2009

We present measurements of average gate errors for a superconducting qubit using randomized bench... more We present measurements of average gate errors for a superconducting qubit using randomized benchmarking [1]. The results are compared with gate errors obtained from a double pi\ pi pi pulse experiment and quantum process tomography. Randomized ...

Bulletin of the American Physical Society, Mar 5, 2015