www.nature.com/articles/s41... I've been saying that entanglement-assisted stellar interferometry is unlikely to become practical in my lifetime, but that won't stop me from shamelessly claiming a little bit of credit every time others make heroic progress in this direction.

www.science.org/doi/10.1126/..., www.science.org/doi/10.1126/... STO has a Pockels coefficient >30x that of lithium niobate at cryogenic temperature. Sounds like a miracle.

Is QCMC dead as well?

"This theory is going to revolutionize the car industry... We assume that the road is a frictionless plane and we won't study what happens when there is friction. We also perform a demo using superfluids." This is what a lot of quantum metrology papers look like to me.

If only everyone were this honest [Stroock, Gaussian Measures]

Thank you for your invitation. I am intrigued by paper, but unfortunately it is against my principles---and indeed common sense---to provide free service for a for-profit company. It is nothing personal and it has nothing to do with the quality of the paper. I appreciate your understanding.

No-cloning theorem in a tweet: define the tensor-product map f(rho)=rho x rho, plug in rho(X) as a function of unknown X, and observe that your favorite info measure (mine is quantum Fisher info) has increased. Since a physical channel can't increase info, f cannot be physical.

For those looking forward to the next edition of the Workshop on Quantum-Inspired Superresolution, previously held in 2021 and 2023 by Zoom (blog.nus.edu.sg/mankei/2nd-w...), sorry that I have not been able to host one this year, but I hope to do it again next summer.

"On-sky Demonstration of Subdiffraction-limited Astronomical Measurement Using a Photonic Lantern." I haven't read the paper yet, but this sounds exciting. iopscience.iop.org/article/10.3... newsroom.ucla.edu/releases/tel...

When I review a bad paper but try to stay diplomatic

www.youtube.com/watch?v=MLh0... Stunning experiment of macroscopic quantum tunneling at room temperature! Widespread applications as well. (not trying to belittle the amazing Nobel achievement at all, just fun to point out)

SQUID and superconducting circuits are cool, but with all due respect the benefit of quantum computing to mankind is not even net positive yet.

The AI has spoken

x.com/arxiv/status... We have this curious phenomenon that the number of papers is exploding in recent years, but Nobel prizes are more often going to older people and older work. What if quantity is negatively correlated with quality?

Putting my thoughts together. Why networks beat "hero" sensors and what birds can teach us. quantum-noise.ghost.io/quantum-sens...

doi.org/10.1109/MSP.... Sad to learn that Van Trees passed away in 2023. His books are for me the perfect balance of principles and practice. For many years they were my secret recipe for my research—just pick a chapter and generalize to quantum.

Quantum Optics Lecture Notes v0.5: the main addition is Appendices K and L on the classical "semiparametric Cramer-Rao bound." (1/2) www.ece.nus.edu.sg/stfpage/tmk/... www.ece.nus.edu.sg/stfpage/tmk/...

A random memory: when I was an undergrad I went to an optics professor for advice; one question I asked was whether I could do research in theoretical optics. He looked at me with disgust and said, "there's nothing left to do in theoretical optics."

Quantum Optics Lecture Notes v0.4: A4 size: www.ece.nus.edu.sg/stfpage/tmk/... Letter size: www.ece.nus.edu.sg/stfpage/tmk/... Added some appendices on open quantum systems and classical statistics. Updated the appendix on probability.

www.physics.nus.edu.sg/faculty/lo-h... Singapore is the hottest place to do physics now!

I heard many talks recently about bounds, and people would just write down inequalities and pretend that they are cool. One famous example is the Cramer-Rao bound for biased estimators en.wikipedia.org/wiki/Cram%C3.... (1/n)

Forgive me if I prefer quantum thermodynamics in the 70's [Lindblad (1975)]

Stop treating the academia like a game; it ends up embarrassing everyone at the institution and not just the offenders. Reputation is hard to build and easy to destroy.

I heard people are interested in quantum sensing of time-varying signals again, so it's time for yet another round of shameless self-promotion: doi.org/10.1103/Phys... doi.org/10.1103/Phys... doi.org/10.1088/1367... doi.org/10.1103/Phys... doi.org/10.1103/Phys... (1/2)

Three recent experimental demonstrations of quantum-inspired superresolution spectroscopy: arxiv.org/abs/2506.20514 arxiv.org/abs/2506.20416 arxiv.org/abs/2506.22767

This will be handy for the new pope

Quantum Optics Lecture Notes v0.3.1 A4 size: www.ece.nus.edu.sg/stfpage/tmk/... Letter size: www.ece.nus.edu.sg/stfpage/tmk/... Updates after teaching PC4246 this semester. Clarifications of common issues, various improvements, and many bug fixes; see cover page for details.

Cool doi.org/10.1038/s413...

Two pandemic-era papers I neglected to promote earlier: (1) For quantum objects that arrive randomly and rarely, the Poisson state is an approximation that leads to neat formulas for many information quantities. doi.org/10.22331/q-2... (1/n)

Talagrand, Quantum Field Theory, Appendix I on Gupta–Bleuler

New application of quantum-inspired superresolution!

An underappreciated invention by Horace Yuen and Vincent Chan: the balanced homodyne detector [ opg.optica.org/ol/abstract.... ], which I covered today in a Quantum Optics class. Simple, elegant, works in practice.

With all due respect, no sane people do volunteer work for for-profit companies. This means that you should not expect me to referee your paper if you send it to a for-profit journal. (If avoiding me is your goal, fair play)

www.nasonline.org/directory-en... Jacob Ziv - Biographical Memoir by Neri Merhav, Shlomo Shamai (Shitz), and Andrew Viterbi

Constance Reid, Hilbert (Springer, New York, 1996), p. 163.

Eve had an entanglement with Alice, and Alice is now gone. How can Bob help Eve get over the heartbreak? The same problem arises in the quantum realm. This work proposes an apparatus, called a quantum reverser, to reverse an interaction of one quantum system with another.

Does anyone have any solid science to report? I'm rather tired of the emperor's latest fashion line.

I guess it's OK to be outrageous in popular summary nowadays right?

physics.aps.org/articles/v18... "The conversion from an interferometric readout to a single-photon detector is really an ingenious idea." We will take a little bit of credit for that! Experiment is the hard part of course.

At what wavelength!?

What's the correct pronunciation of Holevo?

The slides for my presentation on quantum semiparametric estimation at the Heraeus seminar (www.we-heraeus-stiftung.de/veranstaltun...) are now available at drive.google.com/file/d/1co1d...

royalsocietypublishing.org/doi/10.1098/... Re: Sec. 4 on quantum-inspired methods in this review paper by Boyd's group, I wish to point out that, contrary to their assertion, there has been a lot of work on extended sources and general imaging, e.g., arxiv.org/abs/2010.11084 (1/n)

I am delighted to brag that I have published just one paper this calendar year and I am the only author. I challenge everyone else to do the same.

I'm gonna print this FAQ on my business card; I hear it about 3 times a week: "Why aren't you with CQT" "I don't know. Why don't you ask them for me"

Delighted that the GQuEST project by Caltech, JPL, and Fermilab has adopted our 2016 idea of spectral photon counting to enhance their interferometer for noise spectroscopy [https://arxiv.org/abs/2404.07524v2]. When the citation is significant, one is plenty.

Years ago when I read Gottesman's seminal arxiv.org/abs/quant-ph..., I was completely mystified by his "Heisenberg representation": it looks like Heisenberg picture but in the wrong direction. It's a pleasure, at least for myself, to finally find an intuitive interpretation. (1/n)