In this episode, your host Sebastian Hassinger sits down with Andrew Houck to explore the latest advancements and collaborative strategies in quantum computing. Houck shares insights from his leadership roles at both Princeton and the Center for Co-Design of Quantum Advantage (C2QA), focusing on how interdisciplinary efforts are pushing the boundaries of coherence times, materials science, and scalable quantum architectures. The conversation covers the importance of co-design across the quantum stack, the challenges and surprises in improving qubit performance, and the vision for the next era of quantum research.

KEY TOPICS DISCUSSED

• Mission of C2QA:
  The central goal is to build the components necessary to move beyond the NISQ (Noisy Intermediate-Scale Quantum) era into fault-tolerant quantum computing. This requires integrating expertise in materials, devices, software, error correction, and architecture to ensure compatibility and progress at every level.
• Materials Breakthroughs:
  Houck discusses the surprising impact of using tantalum in superconducting qubits, which has significantly reduced surface losses compared to other metals. He explains the ongoing quest to identify and mitigate sources of decoherence, such as two-level systems (TLSs) and interface defects.
• Co-Design Philosophy:
  The episode delves into two types of co-design:
  • Vertical co-design: Aligning advances in materials, devices, error correction, and architecture to optimize the full quantum computing stack.
  • Cross-platform co-design: Bridging ideas and techniques across different qubit modalities and even across disciplines, such as applying methods from quantum sensing to quantum computing.
• Error Correction Innovations:
  Houck highlights breakthroughs like using GKP states for error correction, which have achieved performance beyond the break-even point, thanks to improvements in materials and device design.
• Bosonic Modes and Custom Architectures:
  The conversation touches on leveraging native bosonic modes in hardware to simulate field theories more efficiently, potentially saving vast computational resources. Houck discusses the trade-offs between general-purpose and custom quantum circuits in the current era of limited qubit counts.
• Modular Quantum Computing:
  As quantum systems scale, the focus is shifting to modular architectures. Houck outlines the challenges of connecting modules—such as chip-to-chip coupling and optimizing connectivity for error correction and algorithms.
• Institutional Collaboration:
  Houck contrasts the long-term, foundational investment at Princeton with the national, multi-institutional mission of C2QA. He emphasizes the unique strengths universities, industry, and national labs each bring to quantum research, and the importance of fostering collaboration across these sectors.
• Looking Ahead:
  The next phase for C2QA will incorporate advances in neutral atom quantum computing and diamond-based quantum sensing, while ramping down some networking efforts. Houck also reflects on the broader scientific and practical motivations driving quantum information science, and the fundamental questions that large-scale quantum systems may help answer.

NOTABLE QUOTES

“There’s a quasi-infinite number of ways that you can mess up coherence… If you’re really only using one number, you’ll never know.”

“Some of the best ideas we have are taking approaches from one field and bringing them to another. That’s what we call cross-platform co-design.”

“A million-qubit quantum computer is basically a cat… as you build these systems up, you can start to really ask: do we actually understand quantum mechanics as it turns into these macroscopically large objects?”

RESOURCES & MENTIONS

• Center for Co-Design of Quantum Advantage (C2QA)
• Princeton Quantum Initiative

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