All-In Podcast: Nobel Prize in Physics Winner John Martinis on the State of Quantum

Date: October 27, 2025
Host(s): All-In Podcast besties
Guest: John Martinis, Nobel Laureate in Physics, 2025

Episode Overview

This episode features an in-depth interview with John Martinis, recent Nobel Prize-winner in Physics (2025), celebrated for his pioneering work demonstrating quantum mechanical phenomena at the macroscopic level and foundational contributions to the development of superconducting qubits for quantum computers. The conversation delivers an accessible yet thorough exploration of quantum mechanics, the journey from childhood curiosity to Nobel-winning science, the current state and future of quantum computing, and reflections on the broader implications for the tech industry and scientific discovery.

Key Discussion Points & Insights

1. John Martinis’ Early Life and Path to Physics

• Background and influences
  • Grew up in San Pedro, California, son of a fireman and a stay-at-home mother.
  • Early fascination with building and understanding how things work, influenced by his father's hands-on projects in the garage.
  • "My dad actually didn’t have a high school education, but very smart person. He was always building things in the garage... So I grew up kind of knowing how to build things, which also kind of tells you how things work." — John Martinis [01:08]
• College and academic direction
  • Attended UC Berkeley as an undergraduate, inspired by mentor John Clarke, leading to early research on quantum phenomena in electronic devices.

2. Basics of Quantum Mechanics

• Probability and “fuzziness” at small scales
  • Quantum mechanics deals with probabilities, not deterministic paths:
    • "When you get very, very small, things get very fuzzy and it's very hard." — Host [05:39]
    • "I used to say to my kids that the electrons were fuzzy... You can think of the electrons being all around the nucleus at the same time." — Martinis [06:07]
• Electrons as waves, not particles. Mathematical understanding comes with advanced study, emphasizing the non-intuitive nature of quantum theory.
• Direct analogy and explanations using everyday technologies (memory circuits, magnetic storage) to anchor complex ideas.

3. Quantum Tunneling and Macroscopic Quantum Phenomena

• Quantum Tunneling explained

  • Electrons (or other particles) can “tunnel” through barriers just by the probabilistic, wave-like nature at the quantum level—even when classical physics says they shouldn’t.
  • “Most of the time [an electron] bounces off [the wall], but every once in a while it goes through. And you know, this is seen in everyday devices.” — John Martinis [10:00]

• Extending quantum effects to macroscopic systems (“Schrödinger’s cat” paradox)

  • Introduced by Anthony Leggett (Nobel Laureate), the core experimental question of Martinis’ doctoral research: Can an object made up of billions of atoms show true quantum behavior?
  • “The question was, do macroscopic objects behave quantum mechanically?... In our case, it's an electrical circuit with billions of electrons in it...” — John Martinis [03:55]

• Josephson Junction Experiments

  • Critical component: two superconductors separated by a thin insulator, enabling “Cooper pairs” (paired electrons) to tunnel through with no loss.
  • Demonstrated observable quantum effects (e.g., discrete energy transitions) in large systems.
  • “Then you can effectively measure all of these different changes as you change the temperature... what you demonstrated was that there were these very kind of discrete or specific changes that happened that basically demonstrated quantum mechanics at scale.” — Host [21:02]

4. From Fundamental Physics to Quantum Technology

• Early research impact and Nobel recognition

  • The results were initially “kind of weird,” garnering attention but not immediate practical application.
  • "It was noteworthy at the time, but not necessarily something for a Nobel Prize, because it was just kind of weird and went off and what are you going to do with it?" — Martinis [23:58]
  • Nobel worthiness emerged as foundational experiments spurred decades of further research and the birth of quantum information science.

• Influential encounters and the birth of quantum computing

  • Describes being inspired by Richard Feynman’s legendary talk at UC Santa Barbara on quantum computation.
    • “I was just a lowly graduate student, so I could hear a little bit. But what I learned from this, it was a great question and something that would be kind of worth doing for your life work because it’s so deep and so interesting...” — Martinis [25:39]

5. Quantum Computing: Progress and Challenges

• Definition and construction of qubits

  • Uses superconducting circuits as qubits, built from Josephson junctions, oscillating at gigahertz frequencies.
  • "We set that up to oscillate at about 5 GHz... To form the qubit, this oscillating thing... and at low temperature, superconductors, all this magic. We can get quantum mechanical behavior out of that." — Martinis [30:53]

• Scaling up: From Proof to Practice

  • Led Google’s quantum team, achieving “quantum supremacy” with a 53-qubit system that could perform a specific computation far faster than any known classical computer (2019).
  • Quantum computers today:
    • “Right now we’re about 50 or 100 qubits... They can be fully controlled and run real algorithms... But they aren’t really big enough to be useful yet." — Martinis [36:13]

• Challenges: Noise, Error Correction, and Engineering

  • Qubits are extremely sensitive to errors; large-scale, general-purpose quantum computers will require millions of qubits due to the overhead for error correction.
  • "You’re talking about a million qubit quantum computers to be general purpose and solve really hard problems. There might be some... a million is a good round number for it... And right now we’re at, you know, 100 or a little bit more than that." — Martinis [40:16]
  • Discusses the need for new fabrication techniques and industrial partnerships to enable the next leap.

• Timeline for useful quantum computers

  • Cautiously optimistic, noting constant predictions of “10 more years.”
  • “We think when we get that to work, we can scale up very rapidly in let’s say, 10 year timescale, something like that.” — Martinis [38:18]

6. The Role of AI and Global Competition

• AI’s accelerating influence

  • AI is starting to assist in hardware design, error correction, and simulation, though “building it right” remains paramount.
  • "If you don’t build your system cleanly enough... you’re not going to get the great performance out of it. I’m a little bit old school here and working on building it that way." — Martinis [39:32]

• China vs. the US in quantum science

  • China is making rapid progress, at times matching or closely following US achievements.
  • Concerns about visibility and transparency of China’s advances given possible government-mandated publication lags.
  • “The thing that scares me a little bit is... China soon afterward published something indicating they were on par or near par or something to it." — Martinis [41:48]
  • Leverage is possible from US access to advanced manufacturing equipment not available in China.

7. Reflections on Recognition and Scientific Progress

• Winning the Nobel Prize

  • Recalls “insider” feeling at Nobel symposiums, anticipation, hope, and remaining grounded.
  • “In the past when the dates have come around, it’s like, oh, is this going to happen?... And then you wake up in the morning and it’s like, oh, it didn’t happen. And... that’s a very bad attitude. And you should not covet some insanely difficult prize that only goes to a few people.” — Martinis [44:54]
  • This year, found out from his wife (who let him sleep in so he wouldn’t be “grumpy”):
    • "She woke me up at 5:30... as I looked at the computer. Oh my God." — Martinis [46:41]

• Impact and legacy

  • Celebrates the scale of the field that grew from his early experiments; thousands now work toward practical quantum computers, major companies sell access to experimental quantum hardware.
  • “It just turned into enormous field, large number of papers, large number of people... And the fact that it was a useful idea that led and brought into form all these different experiments, ideas, and many, many people contributed.” — Martinis [33:08]

• Broader lessons on curiosity, invention, and unintended consequences

  • “Sometimes inquisitive minds leads to research that leads to some set of discoveries that are completely not apparent until 40 years later the effect or the impact it may have had...” — Host [33:52]

8. Personal Interests and Forward-Thinking

• Prioritizes focus on his current work (“especially when you start a company”), but is especially excited about quantum devices being used in astronomy, e.g., exoplanet searches with superconducting detectors.
• “That’s particularly interests me... I like building building instruments.” — Martinis [48:28]

Notable Quotes & Moments

• On the Nobel Prize call:
  "She woke me up at 5:30... as I looked at the computer. Oh my God. And then we had some reporters coming over at 6..." — John Martinis [46:41]
• On early quantum computing inspiration:
  “Richard Feynman... was talking about using quantum mechanics for computation, which is building a quantum computer... It was a great question and something that would be kind of worth doing for your life work.” — Martinis [25:18]
• On the state of quantum computing:
  “Right now we’re about 50 or 100 qubits for the superconducting case... but they aren’t really big enough to be useful yet.” — Martinis [36:10]
• On China’s progress:
  “China soon afterward published something indicating they were on par or near par or something to it. I’m worried that the Chinese government is saying, well, you can’t publish anything until it’s in the Western press and then you can...” — Martinis [41:48]
• On the long arc of basic science:
  “Sometimes inquisitive minds lead to research that leads to some set of discoveries that are completely not apparent until 40 years later...” — Host [33:50]

Timestamps for Key Segments

• 00:54 – Martinis’ upbringing, family, early influences
• 03:28 – Anthony Leggett, superfluid helium-3, macroscopic quantum effects
• 06:50 – Wave functions, electrons, quantum probabilities
• 09:25 – Detailed explanation of quantum tunneling
• 13:47 – Schrödinger’s Cat, challenge of quantum superpositions in large systems
• 15:19 – Superconductivity basics, Josephson junction
• 21:10 – Summary of macroscopic quantum tunneling experiments
• 25:18 – Encounter with Feynman, the vision of quantum computation
• 29:11 – Building practical quantum computers, transition to Google
• 30:37 – Structure and physics of a superconducting qubit
• 35:52 – Current state of quantum computing, error correction, scaling challenges
• 38:42 – Timeline forecasts
• 39:13 – Role of AI in quantum technology
• 41:16 – China vs. US quantum research
• 44:19 – Receiving the Nobel call, inside the Nobel process
• 47:33 – Interest in superconducting astronomical detectors

Tone and Style

The episode delivers a mix of technical rigor and practical storytelling, with the host guiding the conversation to clarify complex phenomena for a broad audience while maintaining the natural excitement and humility of a lifelong experimentalist. Martinis frequently grounds abstraction in real-world analogies and his own life, emphasizing both the scientific adventure and the collaborative, incremental nature of progress.

A rich, wide-ranging dialogue about the origins, present state, and future of quantum mechanics and quantum computing—straight from one of the field’s foundational figures.