Macroscopic Quantum Tunneling Enables New Quantum Devices and Computers

StarTalk Radio · January 06, 2026 · Listen to Original Episode →

Original Title: Macroscopic Quantum Tunneling with John Martinis

TL;DR

Macroscopic quantum tunneling in electrical circuits enables the creation of a new "periodic table" of quantum devices, moving beyond atomic-level physics to engineer novel electronic components.
The discovery of macroscopic quantum tunneling in circuits provides a practical pathway to building quantum computers using existing electronic technologies, accelerating their development.
Quantum computers, by leveraging superposition and entanglement, can perform calculations on exponentially more states simultaneously than classical computers, enabling solutions to previously intractable problems.
The development of quantum computers necessitates a transition to quantum-safe cryptography, as current encryption algorithms like RSA will become vulnerable to quantum decryption.
Quantum computing's ability to simulate complex quantum mechanical systems offers potential breakthroughs in fields like materials science, drug discovery, and understanding fundamental physics.
The realization of quantum computing's potential requires overcoming significant engineering challenges related to qubit stability, error correction, and maintaining quantum states.
Quantum computing's immense computational power may enable the simulation of complex systems like the human brain, potentially leading to insights into consciousness and emergent intelligence.

Deep Dive

The 2025 Nobel Prize in Physics, awarded for the discovery of macroscopic quantum mechanical tunneling and energy quantization in an electric circuit, signifies a paradigm shift in our ability to engineer and utilize quantum phenomena. This breakthrough, achieved by John Martinis and his collaborators, moves quantum mechanics from the realm of atomic-scale understanding to practical applications in macroscopic electrical circuits, paving the way for a new generation of quantum electronic devices and fundamentally advancing quantum computing.

The core of the discovery lies in observing quantum mechanical behaviors, specifically tunneling, within electrical circuits roughly the size of a dime. Previously, quantum mechanics was primarily understood at the microscopic level of atoms and molecules. However, the research demonstrated that electrical currents and voltages in these circuits adhere to quantum laws, a phenomenon made possible by phenomena like superconductivity where electrons condense into a unified quantum state. The Nobel-winning work identified a potential energy barrier in superconducting circuits that can be "tunneled" through, analogous to a particle overcoming an energy barrier it classically shouldn't have the capacity to surmount. This observation, while rooted in experiments dating back to 1985, gains its profound significance from its downstream applications.

The practical implication of this discovery is the creation of a new "periodic table" for quantum mechanics, not of elements, but of quantum devices built from components like inductors, capacitors, and Josephson junctions. This enables the construction of electronic devices that inherently obey quantum mechanics, most notably, quantum computers. This opens the door to leveraging quantum computation for tasks intractable for classical computers, such as breaking current encryption algorithms (like RSA), potentially revolutionizing fields from materials science and drug discovery to complex simulations of weather patterns and mapping the human brain. The rapid advancement in qubit counts and quality, alongside the development of specialized algorithms, suggests that quantum computing will transition from a research curiosity to a powerful tool, likely accessed remotely via terminals connected to specialized data centers, rather than as standalone consumer devices.

The long-term consequences of this quantum leap extend to societal structures and our understanding of reality itself. The potential to break existing cryptography necessitates a proactive shift to quantum-safe encryption to maintain digital security. Furthermore, the immense computational power of quantum computers fuels discussions about their role in advanced AI, potentially accelerating scientific discovery and even prompting philosophical debates about the nature of consciousness and the possibility of simulated universes, as the complexity required for such simulations may only be achievable with quantum-level computation.

Action Items

Audit quantum computer architectures: Identify 3-5 common error sources (e.g., thermal noise, radiation) and propose mitigation strategies for improved qubit stability.
Draft quantum-safe cryptography transition plan: Outline 2-3 key steps for migrating existing systems to quantum-resistant algorithms within 5 years.
Evaluate quantum computing applications: Identify 3-5 potential use cases beyond encryption (e.g., molecular simulation, weather prediction) and assess feasibility based on current qubit counts.
Design quantum-safe algorithm testing framework: Define 3-5 test cases to validate the performance and security of new quantum-resistant cryptographic algorithms.

Key Quotes

"very simply we saw an electric circuit where if you look at how it works you it's obeying quantum mechanics it's using the laws of quantum mechanics and what's kind of unusual here is you think of quantum mechanics of how atoms work or molecules work so it's usually on the microscopic small objects and we showed that for electrical circuit which the chip is about you know the size of a dime or so it's it's a quite big it's the current and voltages of that that obey uh obey quantum mechanics"

John Martinis explains that the discovery for which he won the Nobel Prize involved observing quantum mechanical laws in an electrical circuit. This is unusual because quantum mechanics is typically associated with microscopic entities like atoms and molecules, not macroscopic objects like electrical circuits. Martinis highlights that the current and voltages within the circuit itself were found to obey these quantum laws.

"so the basic idea of a qubit it's very much like a bit if you know anything about how your computers work there's a state that can be in zero and one and you put bits together to show a word or describe a number and you do some logic operations with that so what a qubit is is a bit that's made out of a quantum computer and the laws of quantum mechanics can say that it can be both a zero and a one at the same time"

John Martinis defines a qubit by comparing it to a classical computer bit, which can be either a 0 or a 1. He explains that a qubit, being a component of a quantum computer, can exist in a superposition of both states simultaneously due to the laws of quantum mechanics. This ability to be in multiple states at once is a fundamental difference from classical bits.

"so you have the zero and one state and uh you can think about taking a single qubit zero and one state running it through some simple algorithm and then at the end you get the answer for the zero state and you get the answer for the one state and you did all that in parallel because it's not statistical it's a definite definite thing holy crap yeah so now if you have if you have that stacked on stacked on stacked on stacked you can run and you can run countless uh uh calculations at at the same time"

John Martinis elaborates on the power of qubits by explaining how a single qubit can process both its 0 and 1 states simultaneously through an algorithm. He emphasizes that this is not a statistical or probabilistic outcome but a definite state. Martinis then extends this concept, stating that stacking multiple qubits allows for an exponential increase in parallel calculations, leading to the ability to run countless computations at the same time.

"the reason it gets practical is you can now build electronic devices that obey quantum mechanics so the way i like to talk about that is normally people think about the periodic table where you can put the various atoms together to make molecules and you can do useful things with chemistry well what we have here is if we want to look at quantum mechanics we actually have a bigger periodic table now and the new periodic table that we work with are based on inductors and capacitors and things called transmission lines and these josephson junctions and we have a whole new class of quantum devices that we can make based on you know this new kind of physics here this macroscopic physics"

John Martinis explains the practical implications of his research by introducing the concept of a "bigger periodic table" for quantum mechanics. He likens this to the chemical periodic table, which allows for the creation of useful molecules. Martinis states that this new "periodic table" is based on electronic components like inductors, capacitors, transmission lines, and Josephson junctions, enabling the creation of a new class of quantum devices based on this macroscopic quantum physics.

"the universe is only 10 to the 10 years old so to say that a traditional computer would take 10 to the 25 years that's i don't even know what we would have to compute to have to be do it that fast so i mean other than weather forecasting what else needs that level of computing or some clever person's going to say here's something no one thought of because they couldn't have ever calculated it and here it is and now it's done routinely by quantum computers"

Neil deGrasse Tyson expresses astonishment at the computational power of quantum computers, noting that a calculation taking 10^25 years on a traditional computer is vastly longer than the age of the universe (10^10 years). He questions what problems would require such immense computational power beyond weather forecasting, suggesting that quantum computers might enable the discovery of entirely new concepts that were previously impossible to calculate. Tyson implies that this capability could lead to unforeseen scientific breakthroughs.

"well i know one it could be like the mapping of the human brain the uh the neuro synaptic functions of the human brain are so varied and there's so many of them like that be kind of a cool way to figure out and these are applications that people are you know have to discover and work on and the real problem right now is taking whatever quantum computer we have which has some you know limits to its being and then taking the algorithms and try to match them together and do something useful but as soon as you solve really useful problems all the time and let's say money goes into the film the the firms because they're solving useful problems then you can even develop these more this is what happened with uh conventional electronics"

John Martinis suggests that mapping the human brain, with its complex and numerous neuro-synaptic functions, could be a significant application for quantum computing. He acknowledges that a current challenge is matching the capabilities of existing quantum computers with appropriate algorithms to solve useful problems. Martinis believes that as quantum computers become more powerful and solve valuable problems, investment will increase, driving further development, similar to the progression of conventional electronics.

Resources

External Resources

Books

Mr. Tompkins in Wonderland by George Gamow - Mentioned as an inspiration for Michel Devoire's understanding of quantum mechanics.

Articles & Papers

"The discovery of macroscopic quantum mechanical tunneling and energy quantization in an electric circuit" - Mentioned as the research paper that birthed the path to quantum computing.
"The research paper that sort of birth this path" - Mentioned as dating from 1985.
"Obscure research paper" - Mentioned as containing findings about tunneling traversal time.

People

John Martinis - Professor of physics at UC Santa Barbara, Nobel Prize winner for macroscopic quantum tunneling.
Michel Devoire - Co-recipient of the Nobel Prize in Physics for macroscopic quantum tunneling.
John Clark - Co-recipient of the Nobel Prize in Physics for macroscopic quantum tunneling.
Anthony Leggett - Professor whose proposal is related to the phenomenon discussed.
George Gamow - Author of "Mr. Tompkins in Wonderland."

Organizations & Institutions

UC Santa Barbara - Institution where John Martinis is a professor of physics.
Google - Company where John Martinis led a team to develop a superconducting quantum computer.
NIST (National Institute of Standards and Technology) - Government agency with an active program for analyzing cryptographic systems.

Other Resources

Macroscopic Quantum Tunneling - The subject of the 2025 Nobel Prize in Physics.
Superconductivity - Mentioned as a macroscopic manifestation of quantum physics.
Josephson Equations - Mathematical framework used to compute potential barriers in circuits.
Josephson Junctions - Electronic components used in quantum computing.
Cooper Pairs - Pairs of electrons that exist within a superconductor.
Qubit - A bit in a quantum computer that can be in a state of both zero and one simultaneously.
Quantum Supremacy - A term for demonstrating that a quantum computer can perform a task that a classical computer cannot.
Quantum Advantage - An alternative term for quantum supremacy.
RSA - A type of encryption algorithm that may be breakable by quantum computers.
Quantum Safe Crypto - Next-generation cryptography designed to be resistant to quantum computing attacks.
Willow Chip - A Google chip mentioned for its advanced calculation capabilities.
Simulation Theory - The idea that our reality could be a simulation.