Kavan Modi

New study presents a toolkit for describing complex quantum systems with long-range memory, crucial for controlling noise in quantum devices. The work paves the way for advanced numerical techniques and better understanding of diverse quantum systems. 🔗 go.aps.org/3NDAoqM

A unifying operational characterization of quantum chaos is proposed using the formalism of multitime quantum processes. @DowlingNeil_ @modikk @MonashUni @Monash_Science go.aps.org/42pV5gQ

It was nice to watch this video youtu.be/eSGxCYNwFe4?si…

@yudapearl What’s interesting is that the causal view point is unavoidable in quantum theory (quantum stochastic processes). If one insists on sticking to statistics only then they will just get wrong answers for anything beyond two-point correlations.

Several readers contested my statement about pre-causality statisticians. My point is that prior to 1980, statisticians believed that statistics (hence data) is sufficient for science. Typical are the attacks of Niles (1921) and Karlin (1983) on Sewall Wright, see ucla.in/3nis2pS

I’m excited to share a new paper I’ve been working and thinking on for quite a while now. Non-Markovian dynamics have long been elusive to study (or even define) for a variety of reasons. We categorise, efficiently characterise, and control them all!🧵 arxiv.org/abs/2312.08454

Stoked for this work to be out! Complex systems often display long-range correlations. There is a notion of fine/coarse-graining in a spatial setting through hierarchical tensor networks to capture the relevant physics--but what about temporally? scirate.com/arxiv/2312.046…

@gregswhitenoise This was a great a effort where physics came naturally from maths. Great summary @gregswhitenoise

Big congrats to first author Neil Dowling who spear-headed this project, @modikk who's been stewing on the idea for years, and collaborators @RobMuNu and Sukhi Singh also responsible for figuring out many of the details.

Hopefully this will become common knowledge now.

100 logical qubits with error 10^-6 ~10^-8 within next two years!?

Wisdom from Scott Aaronson (1/2): “I think presenting to the public or to investors that we know how to get big quantum speed-ups for machine learning and optimization in the near future is fundamentally dishonest.” politico.com/newsletters/di…

@jenseisert @Tagesspiegel @FU_Berlin @BerlinUAlliance @FraunhoferHHI @HZBde Congrats Jens

Happy to be named among the top 100 researchers of #Berlin, in a survey to be published by the @Tagesspiegel. Berlin offers an excellent academic landscape in a welcoming environment. (For me, primarily the @FU_Berlin of the @BerlinUAlliance, but also @FraunhoferHHI and @HZBde).

@fchollet There is a strong correlation. The reports claiming nonsense are usually written in Word… On the other hand, didn’t Snowden leak a bunch of ppts?

Information does not have more (or less) authority when it is presented in a LaTeX-formatted PDF.

@HyperboIeva For sure. Scrutiny is most welcome. But I genuinely think that there is a clear path forward, with a lot of results to be discovered.

@HyperboIeva I wasn’t familiar with this paper. I agree that the working defs are not identical at a first look. However, this is also true on classical side. There is a hierarchy of related notion that often called quantum chaos. This is very messy, but it is possible to clean this up…

@HyperboIeva Of course, there’s still a lot of open questions. In particular, relating properties of Hamiltonians to those of the process…

@HyperboIeva Also, this tends to unify many different notions of quantum chaos that people tend to argue about. Unsurprisingly, they all have some merit and one can now begin to peel the onion