[Colloquium] Reminder - Reza Jokar Dissertation Defense/Feb 17, 2022

[Megan Woodward]

This is an announcement of Reza Jokar's Dissertation Defense.
===============================================
Candidate: Reza Jokar

Date: Thursday, February 17, 2022

Time: 11 am CST

Remote Location: https://uchicago.zoom.us/j/98201401525?pwd=Uk81eWJzNXlHdlhEOWZ6KzlZYlVXdz09<https://urldefense.com/v3/__https://uchicago.zoom.us/j/98201401525?pwd=Uk81eWJzNXlHdlhEOWZ6KzlZYlVXdz09__;!!BpyFHLRN4TMTrA!sz3vBP_47YPucbO53KsvRD5kroy_zLrfTztm1MA0awo4ntYIvsjlMbHeXtQ5c6HYPiC3RGjU$>  Meeting ID: 982 0140 1525 Passcode: 327563


Title: In-fridge classical controllers in quantum computing

Abstract: Today's superconducting quantum computer prototypes rely on a classical controller at room temperature that controls the qubits inside the dilution refrigerator. This approach is simple and straightforward, however, it introduces significant scalability challenges: (1) quantum error mitigation techniques that are based on room temperature error decoding face exponential latency overhead due to the data backlog caused by the slow decoding process; (2) scalability is limited due to massive costs of generating and routing the microwave control signals.

In this thesis, novel cryogenic controllers are proposed to address the aforementioned challenges. First, we develop an in-fridge classical accelerator for error decoding using ultra-fast superconducting Single Flux Quantum (SFQ) logic technology to avoid the exponential latency overhead. By enabling practical implementation of quantum error mitigation, we expand the compute volume of near-term machines by factors between 3,402 and 11,163. Second, we develop an in-fridge classical controller using SFQ logic to generate and route the control signals inside the dilution refrigerator. We use state-of-the-art SFQ synthesis tools to calculate the power and area of our in-fridge controller, and show that it can operate within the tight power and area budget of dilution refrigerators at >42,000-qubit scales. Finally, we investigate the practical implications of SFQ-based two-qubit gates and show that they can achieve similar gate fidelity and gate time to that of microwave-based gates. The results of this thesis show that cryogenic controllers play a key role in increasing the scalability and computing power of near-term quantum machines.




Advisors: Fred Chong

Committee Members: Hank Hoffmann, Fred Chong, and Massoud Pedram

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://mailman.cs.uchicago.edu/pipermail/colloquium/attachments/20220217/b9dde6f2/attachment-0001.html>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: Reza_Jokar_PhD_Thesis (10).pdf
Type: application/pdf
Size: 2180949 bytes
Desc: Reza_Jokar_PhD_Thesis (10).pdf
URL: <http://mailman.cs.uchicago.edu/pipermail/colloquium/attachments/20220217/b9dde6f2/attachment-0001.pdf>