tags: [podcast, show-notes] status: draft created: "2026-04-27" generated-by: claude-api--- Are We Computing Quantum in the Wrong Base? with Ivan Deutsch From Bell Tests to Albuquerque Ivan started his PhD at Berkeley in 1987, the year of Alain Aspect's Bell-test experiments, drawn into quantum optics by the foundations of quantum mechanics. He learned about quantum key distribution from Artur Ekert at quantum optics meetings, did a postdoc at France Telecom on optical fiber communications, and was at NIST in 1994 when Artur Ekert delivered a colloquium on Shor's algorithm. NIST then hosted Shor himself. Carl Caves recruited Ivan to UNM to help build what was then called an "information physics group" — predating the term "quantum information." Quantum error correction landed shortly after, brought into the group by then-PhD-student Howard Barnum. Why Neutral Atoms — and the Frenemy Relationship with Ions As a NIST postdoc with Bill Phillips, Ivan met Poul Jessen, beginning a 25-year collaboration on optical lattices and neutral-atom control. Ivan frames the trade-off bluntly: ions are great because they're charged (tight confinement, exquisite control) and terrible because they're charged (Coulomb repulsion limits how many you can pack together). Neutral atoms are the inverse — you can trap a million in an optical lattice, but getting them to talk to each other is hard. Inspired by Dave Wineland's ion-trap work, Ivan and Jessen ported sideband cooling and motional-state control to neutrals. Ivan also organized the 1997 Quantum Control of Atomic Motion workshop, which evolved into SQuInT (Southwest Quantum Information and Technology), now in its 26th year. The Rydberg Story — and What the First Paper Got Right The original Deutsch–Jessen proposal envisioned exciting atoms only to a low-lying state; Rydberg blockade came later as a follow-on. Ivan credits co-author Steve Rolston with the framing — "we just wanted to make the whole thing faster" — and notes the full power of the Rydberg blockade wasn't initially appreciated. What the first paper did get right was the architectural idea of moving large groups of atoms in parallel and bringing them together to interact — a feature now central to the roadmaps of Aurora, QuEra, Atom Computing, and Infleqtion. Qudits: Computing Beyond Base Two Ivan is careful not to evangelize, but the question is real: why encode information in two levels when an atom offers many? The information-density gain is only logarithmic (log D / log 2), but the deeper motivation is fault tolerance. He points to Daniel Gottesman's stabilizer formalism, which was originally developed for qudits, and to recent experiments with Mike Martin at Los Alamos on individually trapped strontium atoms with ten-level nuclear spins — "qudecimals." Earlier ensemble work with Jessen demonstrated arbitrary gates on 16-dimensional qudits in cesium. Spin Cat Codes and Biased Error Correction The most compelling argument for qudits may be embedding a qubit inside a qudit using extra levels for redundancy — directly analogous to bosonic cat codes in microwave cavities. Work led by Ivan's colleague Milad Marvian and student Shiva Prasad Omanakuttan introduces "spin cat codes" that exploit the structure of physical noise in atoms. Ivan emphasizes biased error correction: real errors aren't arbitrary, and codes co-designed with the dominant physical error channels — including leakage and erasure errors, which the experimental community has learned to detect and exploit — can dramatically outperform generic schemes. Building a Quantum Ecosystem in New Mexico Ivan stepped in as director of the Center for Quantum Information and Control (CQuIC) when Carl Caves retired in 2018, just as the National Quantum Initiative was taking shape. Recognizing that New Mexico's research strength wasn't translating into economic benefit for one of the country's poorest states, he advocated for industrial engagement. The result: a partnership with Colorado that won the EDA Tech Hub designation as Elevate Quantum — the only quantum-focused tech hub in the country. Internally, he founded the Quantum New Mexico Institute (QNMI), a joint institute spanning UNM, Sandia, and Los Alamos, now led by Bob Ledoux. Quantinuum has opened an Albuquerque facility, QuEra has announced one, and QNet is building a quantum network in the city. Key Takeaways Ivan helped lay the theoretical foundations for neutral-atom quantum computing in a 25-year collaboration with Poul Jessen, by porting ion-trap control techniques to neutral atoms in optical lattices.The original neutral-atom proposal already contained the parallel atom-movement architecture now central to the roadmaps of QuEra, Pasqal, Atom Computing, Infleqtion, and Aurora — but underestimated the power of Rydberg blockade.Qudits offer only logarithmic gains in information density, but may be transformative for fault tolerance, especially via spin cat codes that mirror bosonic encodings within a single atom.Co-design between theory and experiment — and biased error correction tuned to dominant physical noise like leakage and erasure — is accelerating progress more than either could alone.Elevate Quantum (NM + CO) is the only quantum-focused EDA Tech Hub in the U.S., and is rapidly turning New Mexico's decades of academic and national-lab strength into an industrial ecosystem.Chapters 00:01 — From Berkeley and Bell tests to a postdoc at NIST02:14 — Hearing about Shor's algorithm; Carl Caves recruits Ivan to UNM05:04 — The role of Los Alamos and Sandia in New Mexico's quantum ecosystem07:26 — Meeting Poul Jessen; optical lattices and the ion/neutral-atom trade-off12:38 — Founding SQuInT and bridging ion and neutral-atom communities13:29 — Rydberg blockade: what the original proposal got right and what it missed17:50 — Introducing qudits: why compute in base two?22:12 — Fault tolerance, Gottesman's stabilizers, and qudecimals in strontium24:30 — Spin cat codes, bosonic analogies, and biased error correction28:54 — Working at interfaces: theory/experiment, ions/atoms, academia/industry30:48 — Founding QNMI and winning the Elevate Quantum Tech Hub37:18 — What's next: complexity, noise, neutral-atom hardware, and students