New website and upgraded blog

After some consideration, I finally made the effort to get myself a proper domain (mostlyphysics.net), and move my personal web page to a brand-spanking-new Squarespace hosting.

The blog has also moved here from Wordpress, and hopefully I'll manage to update it a bit more often than in the past year – perhaps the extra bells and whistles that this website allows will make it more interesting. 

Welcome!

What the success of the Rosetta mission implies for our view of reality

Philae lander revised search area. Via the New York Times. The European Space Agency's epic Rosetta mission's lost lander has woken up, as reported by the New York Times and many others.

Understanding fairly well the physical principles and the precision required for such accuracy over interplanetary distances, I find endeavors such as Rosetta to be a firm refutation of any radically subjective theories of reality.

No matter how illusory or confounded our picture of the world may be, logic and mathematics seem to grasp something objectively real, out there, uncaring and unaffected by our curiosity, yet reaffirming that science can form the basis of an accurate view of reality.

Just watched a related TED talk: http://www.ted.com/talks/donald_hoffman_do_we_see_reality_as_it_is

Calculating the graphene C 1s core level binding energy

core-holes
core-holes

I have a new article just out, published as a Rapid Communication in Physical Review B. The work is a computational study co-authored with Duncan Mowbray and Mathias Ljungberg from San Sebastian, Spain, and Paola Ayala from Vienna.

As described in the post about my recent review article, X-ray photoelectron spectroscopy is an extremely useful tool for studying the composition of nanomaterials. However, to correlate measurements to actual atomic structures, we need to know their binding energies. In this work, we systematically calculate the core level binding  energy of graphene using two different methods, as described in the abstract:

X-ray photoelectron spectroscopy combined with first-principles modeling is a powerful tool for determining the chemical composition and electronic structure of novel materials. Of these, graphene is an especially important model system for understanding the properties of other carbon nanomaterials. Here, we calculate the carbon 1s core level binding energy of pristine graphene using two methods based on density functional theory total energy differences: a calculation with an explicit core-hole, and an all-electron extension of the delta self-consistent field (ΔSCF) method. We study systematically their convergence and computational workload, and the dependence of the energies on the chosen exchange-correlation functional. The ΔSCF method is computationally more expensive, but gives consistently higher C 1s energies. Although there is a significant functional dependence, the binding energy calculated using the PBE functional is found to be remarkably close to what has been measured for graphite.

You can find the article on the PRB website, or in manuscript form on arXiv.

2014 in review

The WordPress.com stats helper monkeys prepared a 2014 annual report for this blog. "Only three posts in 2014... let's see if I can do more in 2015."

Here's an excerpt:

A New York City subway train holds 1,200 people. This blog was viewed about 7,200 times in 2014. If it were a NYC subway train, it would take about 6 trips to carry that many people.

Click here to see the complete report.

"Could a quantum computer have subjective experience?" by Scott Aaronson

People who are into physics and follow blogs actively have surely ran into MIT physicist Scott Aaronson, probably most well known for his critiques of the alleged D-Wave quantum computer. More recently, Scott has been writing a lot about consciousness, but his latest post – prepared talk notes from the Quantum Foundations of a Classical Universe meeting – is a real doozy. It's a long read but well worth the trouble.

Read More