MA2: Distributed Processing, Network Protocols, and Software Development
Major Activity 2: Distributed Processing, Network Protocols, and Software Development
Research Leads: Eric Chitambar (University of Illinois Urbana-Champaign) & Andrew Cleland (University of Chicago)
Objective: Achieving practical distributed quantum computing and networking that leverages hybrid architectures requires new approaches to protocols and software. To tackle this problem, HQAN researchers employ a software toolchain development approach that is concurrent with hardware advancements. This convergent HQAN approach is interdisciplinary—computer science, electrical and computer engineering, mathematics, and physics theory and software researchers will be co-located and embedded with engineers and experimenters at the HQAN testbeds. HQAN researchers will target identifying methods for validating and optimizing distributed, hybrid processors and developing new applications and protocols that take advantage of this architecture. Close-knit interactions with the HQAN partners will leverage key ideas and lessons learned from pioneering activities such as Google Circ, IBM Qiskit, and the IBM Q Experience.
Validation of “Quantumness”—In collaboration with industry partner Xanadu, we developed a numerical optimization suite that can compute (in real-time) an optimal choice of state preparation and measurement settings for verifying that a noisy quantum channel can transmit entanglement [1]. The method uses a variational quantum algorithm approach that has led to further tests of quantumness in distributed systems [2, 3]. Additionally, conventional simulation methods have been improved for simulating the behavior of noisy entanglement, thereby sharpening the boundary between classical and non-classical phenomena [4, 5].
Tools for practical & modular hybrid computing—HQAN has contributed to the full quantum computing stack on near-term hardware. At the lowest level of the computing stack, HQAN experimentalists and theorists worked closely to co-design optimal chiplet size and connectivity for modular quantum computing in the presence of noise [6, 7]. Additional improvements in computing architecture and circuit design have been proposed for transmon superconducting processors [8], trapped ion systems [9], and cloud quantum cloud computing platforms [10]. Toward the higher end of the stack, we developed novel error mitigation [11], circuit compilation [12, 13], and tomographic techniques [14] that have already demonstrated how intelligent software and circuit design can make quantum computers more expressive. For example, the Variational Approach to Quantum Error Mitigation (VAQEM) package provides greater noise robustness for variational quantum algorithms by incorporating error-mitigation choices into the optimization problem.
Protocols & applications—HQAN work has also yielded new quantum information protocols and applications. We proposed novel entanglement distribution methods [15, 16, 17], which may involve multipartite entangled states shared among many qubits [18, 19], and we have successfully demonstrated some of these in our superconducting testbed [20]. More generally, our team has tackled the problem of efficiently building resource states for quantum computing across distributed networks, such as graph [21] and matrix product states [22]. In the application space, we have proved new protocols for secure tasks on near-term hardware, such as quantum secret sharing [23] and distributed multi-party computation [24].
Project Descriptions
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Validation of “Quantumness”: Campbell, Clark, Solomonik, Suchara Project Contact: Chitambar The goal of this project is to develop computing entanglement measures for families of multipartite states and experimental tests to certify their values. One focus is on deriving upper and lower bounds on the tensor rank of stabilizer states. A second research direction is exploring device-independent tests to validate the dimension of quantum channels in general prepare-and-measure networks. |
Image Credit: Chitambar Lab |
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Protocols and Applications: Chong, Clerk, Junge, Kwiat, Lutkenhaus, Saffman, Suchara Project Contact: Chitambar For this project, HQAN researchers will develop low-dimensional quantum communication protocols that can be implemented on HQAN hardware within the next three to five years. Targeted applications are quantum fingerprinting and distributed phase estimation. In addition, HQAN researchers are advancing the study of resource costs for implementing nonlocal quantum gates. |
Image Credit: Clark Lab |
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Tools for Practical Distributed Computation: Campbell, Chitambar, Chong, Clark, Solomonik, Suchara Project Contact: Clerk We are focusing on developing new theoretical approaches and modelling tools that will allow one to better understand and exploit the properties of hybrid quantum networks, with an explicit focus on near-term experiments. Our approach incorporates both methods coming from computer science and formal quantum information theory, as well as approaches motivated by theoretical physics. In the first category, we have been developing new numerical network modeling tools, new approaches to distributed compilation, and methods incorporating circuit-cutting approaches. In the second category, work has focused on using methods based on engineering dissipation to stabilize remote entangled states (both continuous-variable photonic states and qubit-like states). |
Image Credit: Clerk Lab |