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<div class=""><span class="" style="font-size:14.666666984558105px">This is an announcement of Reza Jokar's Dissertation Defense.</span><br class="" style="font-size:14.666666984558105px">
<span class="" style="font-size:14.666666984558105px">===============================================</span><br class="" style="font-size:14.666666984558105px">
<span class="" style="font-size:14.666666984558105px">Candidate: Reza Jokar</span><br class="" style="font-size:14.666666984558105px">
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<span class="" style="font-size:14.666666984558105px">Date: Thursday, February 17, 2022</span><br class="" style="font-size:14.666666984558105px">
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<span class="" style="font-size:14.666666984558105px">Time: 11 am CST</span><br class="" style="font-size:14.666666984558105px">
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<span class="" style="font-size:14.666666984558105px">Remote Location: </span><a href="https://urldefense.com/v3/__https://uchicago.zoom.us/j/98201401525?pwd=Uk81eWJzNXlHdlhEOWZ6KzlZYlVXdz09__;!!BpyFHLRN4TMTrA!sz3vBP_47YPucbO53KsvRD5kroy_zLrfTztm1MA0awo4ntYIvsjlMbHeXtQ5c6HYPiC3RGjU$" class="" style="font-size:14.666666984558105px">https://uchicago.zoom.us/j/98201401525?pwd=Uk81eWJzNXlHdlhEOWZ6KzlZYlVXdz09</a><span class="" style="font-size:14.666666984558105px">
Meeting ID: 982 0140 1525 Passcode: 327563</span><br class="" style="font-size:14.666666984558105px">
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<span class="" style="font-size:14.666666984558105px">Title: In-fridge classical controllers in quantum computing</span><br class="" style="font-size:14.666666984558105px">
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<span class="" style="font-size:14.666666984558105px">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.</span><br class="" style="font-size:14.666666984558105px">
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<span class="" style="font-size:14.666666984558105px">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.</span></div>
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<span class="" style="font-size:14.666666984558105px">Advisors: Fred Chong</span><br class="" style="font-size:14.666666984558105px">
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<span class="" style="font-size:14.666666984558105px">Committee Members: Hank Hoffmann, Fred Chong, and Massoud Pedram</span>
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