Program

SESSION 3: Semiconductor QIP and tomography (Pavilion I - III)

Chair: Robin Blume-Kohout (Sandia)
1:30 pm - 2:15 pmSusan Coppersmith, (Wisconsin-Madison)
Building a quantum computer using silicon quantum dots

Abstract. This talk will discuss work at University of Wisconsin-Madison that aims to build a quantum computer using electrically-gated quantum dots in silicon. We have proposed and implemented a new "hybrid quantum dot qubit," which has an attractive combination of speed and fabrication simplicity [1]. Recent experimental and theoretical results demonstrating substantial progress towards high fidelity operation will be presented [2,3]. [1] Z. Shi, et al., Phys. Rev. Lett. 108, 140503 (2012). [2] D. Kim, et al., Nature 511, 70 (2014). [3] D. Kim, et al., npj Quant. Inf. 1, 15004 (2015). This work was supported in part by ARO (W911NF-12-0607), NSF (PHY-1104660), and ONR (N00014-15-1-0029).

2:15 pm - 2:45 pmSeth Merkel, (HRL)
Applying benchmarking protocols to encoded qubits with non-Markovian errors

Abstract. An essential goal for any quantum information processing platform is to develop the tools necessary to validate high-fidelity quantum gates. This effort has produced a suite of benchmarking and tomographic protocols that have been applied to a wide variety of physical implementations. All these protocols, however, were designed with strict error assumptions that can and will be violated by physical errors, especially as we push to lower and lower error rates. In this talk we look at randomized benchmarking with encoded states (from which leakage errors may occur) in the presence of non-Markovian noise and under the influence of sequence-length dependent filtering errors. These circumstances may apply to a variety of physical systems, but are particularly pertinent for 1/f charge noise and hyperfine leakage noise in electrically controlled quantum dot qubits. We demonstrate how these errors affect the outcome of randomized benchmarking, including the signatures of said errors and the confidence with which we can report an average gate fidelity.

2:45 pm - 3:15 pmCharles Baldwin, Deutsch group (New Mexico)
Informational completeness in bounded-rank quantum-state tomography

Abstract. Quantum-state tomography is a demanding task, however, it can be made more efficient by applying prior information about the system. A common prior assumption is that the state being measured is pure, or close to pure, since most quantum information protocols require pure states. Measurements of pure states can be constructed to be more efficiently than measurements of an arbitrary state, and for these types of measurements, there exists two different notions of informational completeness. One notion, called strict-completeness, is more useful for practical applications since it is compatible with convex optimization and is robust to noise. We present a unified framework for both notions of completeness for a certain type of measurements. These are measurements that allow algebraic reconstruction of a few density matrix elements. The framework also aids in the construction of new strictly-complete measurements. Moreover, the results are easily generalized to the case when the prior information is the state has bounded rank.

SQuInT Chief Organizer
Prof. Akimasa Miyake
amiyake@unm.edu

SQuInT Co-Organizer
Prof. Elohim Becerra
fbecerra@unm.edu

SQuInT Founder
Prof. Ivan Deutsch
ideutsch@unm.edu

SQuInT Administrator
Gloria Cordova
gjcordo1@unm.edu
505 277-1850

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