Instability of Quantum de Sitter Spacetime

New paper! We show that quantum effects (in particular, the horizon temperature originally discovered by Gibbons and Hawking) modify the geometry of de Sitter spacetime. Instability of Quantum de Sitter Spacetime (http://arxiv.org/abs/1501.00708) Chiu Man Ho, Stephen D. H. Hsu Quantized fields (e.g., the graviton itself) in de Sitter (dS) spacetime lead to particle production: specifically, …

More

Quantum GDP

  “It’s been only half jokingly said that today a third of GDP is attributable to quantum mechanics,” — former Lockheed CEO Norm Augustine. I’ve heard the one third or 30% of GDP figure from time to time, but have never seen a detailed analysis. A list of modern technologies that arose from quantum mechanics …

More

Feynman Lectures: Epilogue

The full text of The Feynman Lectures is now available online. These lectures were originally delivered to satisfy the physics requirement for first and second year students at Caltech. Legend has it that as the lectures went on, fewer and fewer undergraduates were seen in attendance, with their places taken by graduate students and even members …

More

Wandering physicists

This is funny, and does capture the tendency of physicists (not just old ones) to wander into other fields. But the cartoon avoids the hard question (perhaps best addressed by historians of science) as to the actual value brought to other fields by physicists. See, for example, Physicists can do stuff, Prometheus in the basement, …

More

Nifty papers I wrote that nobody knows about (Part 4: Complex Langevin equation)

This is the last installment of the “Nifty Papers” series. Here are the links to Part1, Part2, and Part 3. For those outside the computational physics community, the following words don’t mean anything: “The Sign Problem“ For those others that have encountered the problem, these words elicit terror. They stand for sleepless nights. They spell despair. They make grown men …

More

Nifty papers I wrote that nobody knows about: (Part 3: Non-equilibrium Quantum Statistical Mechanics)

This is the third part of the “Nifty Papers” series. Link to Part 1. Link to Part 2. In 1999, I was in the middle of writing about quantum information theory with my colleague Nicolas Cerf. We had discovered that quantum conditional entropy can be negative, discussed this finding with respect to the problem of quantum measurement, separability, Bell inequalities, as well …

More

Physicists Create Water Tractor Beam

A group of physicists have discovered that they can make objects move against the direction of waves by using a tractor beam on water, which generates waves. This has important real-world applications, including confining oil spills. The physicists do not yet know mathematical theories explaining how it works.  Dr. Horst Punzmann said ” . . …

More

HKUST IAS

I have a new candidate for coolest research institute architecture. HKUST’s Institute for Advanced Study is housed in an amazing building with a view of Clearwater Bay in HK. The members of the institute will be mostly theoretical physicists and mathematicians :-) Stiff competition from Benasque’s Center and the Perimeter Institute, however. Also Caltech’s IQIM! …

More

Physics and the Horizons of Truth

I came across a PDF version of this book online. It contains a number of fine essays, including the ones excerpted from below. A recurring question concerning Godel’s incompleteness results is whether they impact “interesting” mathematical questions. CHAPTER 21 The Godel Phenomenon in Mathematics: A Modern View: … Hilbert believed that all mathematical truths are …

More