Quantum codes protect quantum states from the outside world. Unfortunately, that also makes it difficult to manipulate them. So far, logical gates were found using ad hoc procedures. In scirate.com/arxiv/2410.162… we introduce a framework that lets us find these operations. 1/5

In this work arxiv.org/abs/2410.18928 with Muzhou(Richard) Ma, Steve Flammia, and John Preskill, we tackle the problem of learning a non-local Hamiltonian with Heisenberg-limited scaling. Specifically, we focus on efficiently learning a k-body Hamiltonian without any geometric structure.

What happens when entangled particles fall into a black hole? Here is what three computer scientists believe... 🧵New paper with Seyoon Ragavan and Vinod Vaikuntanathan

The final PhD project of Oscar Higgott has been published in PRXQ. We show that certain Floquet qLDPC codes can be significantly more efficient than surface codes.

New paper out, entitled "Quasi-optimal sampling from Gibbs states via non-commutative optimal transport metrics" arxiv.org/pdf/2412.01732 Given a local commuting Hamiltonian, when can we prepare efficiently the Gibbs state associated with it using dissipation?

Lately I've been seeing a lot of hype around quantum computing on this platform. Are those bots or humans? Either way, what I'm seeing is concerning. I want to provide an honest perspective on the current status quo, which is hopefully useful. Long story short, I do think a lot

1/5 Excited to share our latest work where we introduce a new phase of matter - the Topological Quantum Spin Glass (TQSG). It combines features of spin glass order and topological order in a fundamentally new way. scirate.com/arxiv/2412.132…

After five years of quantum advantage claims and challenges, I needed to sort things out in my head. The result is a review article "A brief history of quantum vs classical computational advantage" which I hope is useful to experts and non-experts alike: arxiv.org/abs/2412.14703

New paper out about "Belavkin-Staszewski Quantum Markov Chains", the analogues of QMCs for the BS-entropy! arxiv.org/pdf/2501.09708 We study their structure and some properties and applications, see Andreas Bluhm post. Thanks to him, Pablo and Anna for a great collaboration!

From runtimes of decades to hours. Can we bring it down to minutes?

the surface code is officially on notice.

Fig. 2 (Ghiblified)

I have a new paper out: "Quantum Circuit Lower Bounds in the Magic Hierarchy".🔮🪜 arxiv.org/abs/2504.19966 a thread:

We cut the cost of simulating key molecules to hours on future quantum hardware. Now we reveal the technique behind it: sum of squares spectrum amplification (SOSSA)—a new tool for quantum simulation. New paper: scirate.com/arxiv/2505.015…

Happy to share that some previous work with Anirudh Krishna and John Preskill that we call hierarchical codes (2303.04798) was recently published in Quantum! 1/10

Out today in J. Am. Chem. Soc.: We carry out the first simulation of chemical dynamics on a quantum computer! Check out the University of Sydney press release: sydney.edu.au/news-opinion/n…

With Akshar, Yiyi Cai, and Yu Tong we prove high-temperature fermionic Gibbs state is a probabilistic distribution over Gaussian states. Very proud of Akshar and Yiyi --- undergraduates at Caltech! My first experience working with undergraduates! scirate.com/arxiv/2505.097…

New paper today! Very excited to announce we obtain, from first principles, a quantum master equation that both applies in the many-body regime and provably converges to the exact Gibbs state: arxiv.org/abs/2505.20064

I've been sitting on this result for some time because it seemed too crazy to be true. I really hope I didn't make any stupid mistakes! arxiv.org/abs/2506.15147 A 🧵 on why I think this is a rather strange result.

POV: You think you're attending a quantum gravity conference, but it's just a Lenny Susskind birthday party in disguise.