Michael Ragone

New postdoc openings in our group at UC Berkeley! If you wanted to develop hybrid platforms with neutral atom qubits - reach out (CV attached). Deep experimental experience in AMO, superconducting circuits, or quantum optics (with matter qubits) will be highly relevant!⚛️

Looking forward to the Open Quantum Systems conference this week at IPAM at UCLA! It’s a really exciting field and there’s a ton of great speakers here. If you’re around, say hi and let’s grab a coffee. ipam.ucla.edu/programs/works…

LANL's 2026 Quantum Computing Summer School applications are now open. Please apply here 👇 academicjobsonline.org/ajo/jobs/31108

Quantum folks use this observation on the daily. But I’m just always struck by how deep that statement is.

Love teaching Fourier stuff. It’s just so rich and I learn something every time I prep a lecture. Even the basic calculations are just rife with insight—lately, I can’t stop thinking about the theme of “the Fourier transform diagonalizes translations”.

Our group is looking to hire postdocs to work at the intersection of quantum computing, quantum algorithms, quantum machine learning, simulation of many-body quantum systems and early-fault tolerant quantum computing Apply here: lanl.jobs/search/jobdeta… Re tweets appreciated!

@MathMatize Too true.

Don't drink and derive

For reference, I think the story in Hunter and Nachtergaele’s “Applied Analysis”, math.ucdavis.edu/~bxn/applied_a… , chapters 6-7 is really nice. But it’s too technical for my audience.

I have a reference request. I want a physics undergrad friendly book, freely available through a university library, which develops Fourier series/transforms from the perspective of L2 as a Hilbert space.

I feel like this is such a natural thing, and yet every reference I find either doesn’t give a coherent story for the Hilbert space picture or is too mathematically advanced for my students.

@MartinLaroo What a nice result! Do you think this might have implications for the existence of (or lack thereof) of pseudorandom G-ensembles?

How fast can quantum circuits compile group designs? Recent work arxiv.org/abs/2407.07754 showed that designs over the n-qubit unitary group can be compiled in logarithmic-in-n depth. Can we similarly build short-depth designs over other groups? In a new paper arxiv.org/abs/2506.16005, we answer this question negatively.

@GuanniQu Very cool, I’ve never thought about this.

When the wheel loses grip on the road while turning, caster angles ensures that the inertial movement points away from the turn, allowing self-centering.

The caster angle is actually a really interesting and essential part of the bike, here’s the reasons why:

@lorenzo_leone_ Exciting work!

Excited and nostalgic that we finally posted our work on the Clifford commutant: arxiv.org/abs/2504.12263. It started 3 years ago with my PhD thesis, and it's only thanks to my wonderful co-authors that it turned out so complete and nice in the end.

@d0llp4rtsz Topological invariants may only be disrupted by discontinuities—these are phase transitions. States which support nontrivial topological invariants (whatever that means) are called topologically ordered. en.m.wikipedia.org/wiki/Topologic…

@d0llp4rtsz The short version is that “topological” in physics indeed connects to topology in math. The physics of materials are governed by Hamiltonians (self-adjoint operators on a typically very large Hilbert space). These encode energy from interactions and background potentials.

@d0llp4rtsz Topology comes into play when you consider perturbations of these Hamiltonians (think changing the interaction strength, or turning on a magnetic field). If a quantity remains unchanged under continuous perturbations, we call it a topological invariant, or just topological.

Exciting stuff!

Time for @JointMath! Alongside Carlos Ortiz Marrero and Jason Saied, I’m organizing the sessions on variational methods in quantum computing on Thursday, and presenting in the 2nd session on topological insulators on Friday. Lots of great talks lined up, hope to see you there!

@MvsCerezo @qZoeHolmes I wouldn’t mind some notes on this. Could you send me them?

The struggle is real... I have asked @qZoeHolmes a shameful amount of time to share some notes she has on this topic.