Dave Bacon

In this SFI Seminar, biographer Alec Nevala-Lee explores the life of physicist and Nobel laureate Luis W. Alvarez, whose work spanned the Manhattan Project, investigating the JFK assassination, and developing the asteroid theory of dinosaur extinction.

youtu.be/F4KGgtxNF58

Fault-tolerant logical measurement just got a lot faster!

In new work, we show that code surgeries based on hypergraphs, rather than graphs, allow fast and parallel fault-tolerant logical measurements with low qubit overhead (without requiring the code to be single-shot).

arxiv.org/abs/2510.14895

I’ll take “What is the fixed point of LLMs” for $200 Alex.

Coming out of social media hibernation to ask:

Are you interested in hosting a future QEC conf?

We are looking for detailed bids for QEC27 over the next month (provisional deadline 21st November). For more info: DM or email me.

QEC26 will be in Santa Barbara

Dear funding agencies,

I know we all want to discover the wonder drug that will cure the horrible diseases, but to do that, we need to invest in basic, unsexy, foundational research on how the systems work. Funding can’t all be drug development.

Sincerely,
Looking for basic research grants.

Destroying a national treasure.

A one-world interpretation of quantum mechanics The measurement problem is the issue of explaining how the objective classical world emerges from a quantum one. Here we take a different approach. We assume that there is an objective classical syste...

What if the measurement problem isn't about explaining how the classical world emerges from the quantum world...

...but about what happens when quantum systems interact with something that's already classical?

Turns out, the collapse postulate + Born rule emerge!
scirate.com/arxiv/2510.0...
🧪⚛️🧵1/5

MIT rejects Trump administration deal for priority federal funding MIT is one of the nine schools that were asked to agree to adopt conservative priorities and policies in exchange for funding perks.

This is what courage in the face of authoritarianism looks like. No university should take Trump's bribe & surrender their integrity — bending the knee to a bully only feeds the beast & puts ALL our rights at risk.

Others should follows MIT’s example ASAP.

A resource theory of gambling Betting games provide a natural setting to capture how information yields strategic advantage. The Kelly criterion for betting, long a cornerstone of portfolio theory and information theory, admits an...

scirate.com/arxiv/2510.08418 and scirate.com/arxiv/2510.0... with Renato Renner, Takahiro Sagawa, and Philippe Faist. We find a risk–reward trade-off governed by Rényi divergences. The resource theory framework unifies gambling, utility theory, and hypothesis testing. 2/

Renyi divergences emerge when agents bet (or "invest" as some people call it), over a finite number of rounds. In the limit of an infinite number of bets we recover the Kelly Criterion, given in terms of Relative entropy distances (KL divergences). Such a fun project! 4/4

PRL made us remove the word supercoherent from the title (no new words in title is policy) but we still used it in the paper.

Coherence-Preserving Quantum Bits Real quantum systems couple to their environment and lose their intrinsic quantum nature through the process known as decoherence. Here we present a method for minimizing decoherence by making it ener...

Or at least that is what I sort of remember when I looked at this many careers ago. It was partly what inspired arxiv.org/abs/quant-ph... which we originally called “supercoherent” for this reason.

So for entanglement the state is mostly like a product of a lot of two electron entangled states, with the crazy thing that the phase in the entangled states is the same (that is the macroscopic phase, conjugate to the number operator)

*Cooper fun fact: Cooper pairs are error detecting codes, a singlet and a space part that is a symmetric |k,-k>+|-k,k>

Quantifying ground state entanglement of the BCS model The concept of local concurrence is used to quantify the entanglement between a single qubit and the remainder of a multi-qubit system. For the ground state of the BCS model in the thermodynamic limit...

The relevant state is probably the BCS ground state? Though it is an ansatz arxiv.org/abs/quant-ph... so it’s macroscopic in that it’s a large number of things that are like copper pairs.

for the EPA legally to use the report under Information Quality Act guidelines) and (2) hey, there’s an 85+ author, 450-page review of the cherry-picking, misrepresenting, selectively citing DOE report there to discuss (and which Koonin conveniently ignores, talk about pot calling the kettle black)

2025 Physics Nobel: Macroscopic quantum tunneling As announced this morning, the 2025 Nobel Prize in Physics has been awarded to John Clarke , Michel Devoret , and John Martinis , for a ser...

🧪⚛️ The 2025 Nobel Prize in Physics - a brief writeup about what is meant here by macroscopic quantum tunneling. nanoscale.blogspot.com/2025/10/2025...

Jinx

All sound awesome, but am a bit intrigued by the connection between quantum logic and projective geometry

Macroscopic quantum coherence still blows my mind.

Tradeoffs on the volume of fault-tolerant circuits Dating back to the seminal work of von Neumann [von Neumann, Automata Studies, 1956], it is known that error correcting codes can overcome faulty circuit components to enable robust computation. Choos...

Nice result on inherent size of fault-tolerance scirate.com/arxiv/2510.0...

"Our work contributes to this broader effort by providing evidence of inherent limits: Even when codes
have good rate, there may be fundamental constraints on how much they can reduce the volume of
fault-tolerant circuits."

Portland is, I can attest from many personal visits, not a disaster or whatever hate that is tossed at it by people who don’t know how to love. We’re with you southern neighbor.

Why hasn’t Shor won the Turing award? Inquiring minds want to know. (And Alan Turing would love it, he actually wrote some stuff on the foundations of quantum theory…a sort of argument that the Zeno effect was deadly for measurement problem iirc)

Charlie Bennett should win the Nobel prize in Physics this year.

Like...this is the biggest corruption scandal the NIH has experienced in its entire history and its not even close. Half of a BILLION dollars to a single project as a result of political spoils. That's the equivalent of several hundred R01s.

I see Oedipa Maas crying

CU computer science is doing a search for a tenure-track position in quantum computing this year: jobs.colorado.edu/jobs/JobDeta.... The scope of the search in particular includes quantum CS theory!

AMA about how awesome Boulder and Colorado are!

Not sure why the extra E appeared here lol.

We’re scaling quantum computing even faster with Atlantic Quantum. Google Quantum AI was founded in 2012 and our mission today remains the same — build quantum computers that can solve otherwise unsolvable problems. We’re making steady …

blog.google/technology/r...

E

Oh man I don’t think I’m up to that this is complex stuff that I barely grok. Maybe I’ll try to blog about it using the simplest example of how all this works. Dear universe please give me extra time to do fun stuff.