New Physical Review Letters Paper is out

Researchers at Washington State University use Patterns to set Limits on Light/Matter Interactions

 

Physicists Rick Lytel, Sean Mossman, Ethan Crowell and Mark Kuzyk at Washington State University are developing general principles that can be applied to making new materials that harness light.   Beefed up light-matter interactions can be used to make higher-contrast medical images, more effectively burn cancer cells while leaving healthy ones intact, suppress the twinkle of stars in telescopes, supercharge the internet, make lasers more colorful and effortlessly process complex images.  The new has appeared in the August 18^th 2017 issue of Physical Review Letters.

Researchers typically model each new candidate material with complex equations that are difficult to interpret.  Rather than evaluate specific materials using this obtuse formalism, the WSU team instead studies the structure of the equations to search for patterns that hint at the largest possible response.  Since the equations are intractable, the researchers instead throw metaphoric darts at the target, but constrain the trajectories using the sum rules -- physical laws that must be obeyed by a quantum system.  After many throws, and applying a filter that takes into account the effect of molecule size, a pattern comes into focus.

The pattern reveals the true fundamental limits to be about 30% lower than previously calculated and suggests that a potentially new design paradigm will be required to get to the limit.  Ongoing work is aimed at translating the physicists’ esoteric findings into rules that can be used by chemists, materials scientists and nanotechnologists to make better materials.

The present work resolves several puzzles.  The theory of the fundamental limits of light/matter interaction strength predicted a ceiling that was almost 50% higher than all theoretical models, suggesting that exotic materials were needed to bridge the gap.  The new work shows that such unphysical quantum systems are not required to reach the limits and that exotic systems will likely obey the same limit.  Furthermore, infinities in the older incomplete theory – warning flags in physics of theoretical pathologies -- have been excluded by the new results.

While the present work has practical implications for new technologies, the search for patterns generated by constrained random sampling is a powerful tool that can be applied to understanding the underlying structure of complex theories.  In future work, the WSU researchers plan to apply this approach to a holistic investigation of the combined properties of a material needed for specific applications, and identifying the path for getting there.

What Ever Happened to Civili Discourse

I am getting so numb to the rhetoric on all the news networks that I have forgotten the civility of those Obama years that Trump supporters and many republicans point to as the evil Obama era.  He was called a liar, illegitimate, and far worse, but remained a gentleman.  The other night, MSNBC posted a video of the then new commander in chief in 2010 taking questions from the audience. Below is an excerpt.


Obama reacts with polite banter to Wall Street guy Anthony Scaramucci (Trump's new white house communications director), who is critical of Obama's handling of the aftermath of the burst housing bubble.  There is no name calling.  Obama sates the facts (which are verifiable) in support of his reasoning to tax the wealthy at the same rate as their low-paid secretaries. Scaramucci is ashamed by the facts.

This is how issues should be debated.  I would feel far more comfortable with Trump's presidency if he gave an open town hall meeting (not a rally aimed at his diehard supporters) were he responds to critics with reasoned answers.  Instead, he rants about crowd size, inflates his accomplishments by counter-factually huge amounts, and makes disparaging remarks about anyone who disagrees with his warped view of reality.  This in turn releases a frenzied response from liberals who are attacked by conservatives in an endless and escalating cycle.  This must stop.

Let's come together as Americans who love the freedoms and institutions that make this country great and debate the issues with civility, calling upon facts to make measured arguments.  Let's quote legitimate sources rather than ideological echo chambers.  Let's respect each other's views without dismissing our ideological opposites.  We can disagree and debate, but let's not call each other names or brand members of a group by their most extreme members.

I challenge all of us to start an honest and sincere grass roots movement of civil discourse where everyone can voice his or her own opinion, not to convince others, but to bring clarity to the motivations of those with whom we disagree.  Hell with our leaders; let's resolve our differences at the local level, where it matters most, and let it percolate upward to those who represent us.

I strongly urge newspapers and other media to play a more active role in mediated debate.  Encourage pairs of writers or bloggers with opposing views to weigh in on the same issue, perhaps even encouraging a back-and-forth exchange, calling upon fact checkers to enforce honesty.  If we're lucky, perhaps civil discourse will once again become the norm.   We can accomplish so much more if we work together and use reality, peppered with reasoned opinion, as the the basis for making decisions.

Anderson Windows Bad Screen Design

All of our new Anderson casement windows have two clips to hold the screen. The screens bow, so there is more than a 0.5" gap at the top and bottom, letting in the bugs.  The video above shows a video of the gap as I push on the screen.  The model numbers can be found on the stickers as shown below. 

A Short Note On How We Know About Anthropomorphic Climate Change

The purpose of this post is to provide a simple explanation for how we know with a high degree of confidence that climate change is due to humans.

The plot shows the land-ocean temperatures for the years that saw a huge increase of the quantity of carbon that humanity has added to the atmosphere.  The points are yearly values and the red curve a five-year average, which smooths out the fluctuations to highlight the general trend (source: NASA with data at https://data.giss.nasa.gov/gistemp/graphs_v3/Fig.A2.txt).  The shaded area shows the total carbon emission each year from human activities (source: Department of Energy with data at http://cdiac.ornl.gov/ftp/ndp030/global.1751_2011.ems).

I won't go into details of how heating of the oceans and air affect climate because this phenomenon is well known and not a topic of debate.  The point of contention is proof that humans are responsible.  The plot shows excellent correlation between the mass of greenhouse gasses that are emitted by human activities and the temperature.  But correlation is not proof of causation, so how do we know that we are to blame?

The science is too complex to argue in a public forum.  The reason for the high degree of certainty is based on the many different streams of evidence that converge on the same conclusion.  It's like all compasses pointing to magnetic north; those that don't are found to be broken and point randomly, refuting the assertion that the vast number of north-pointing compasses must be wrong.

This convergence of many independent lines of evidence in support of a conclusion is called consilience, a topic that is well explained by Michael Shermer in Scientific American, and can be found at https://www.scientificamerican.com/article/why-climate-skeptics-are-wrong/.  This is a must read for all non-scientists who want to understand how science works and why it is so reliable.

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Some people may blame scientists, who base professional judgements on extensive knowledge and consilience, of being arrogant.  A proclamation of a "truth" that goes against the accumulated evidence of a scientific field is true arrogance.  Basing policy that goes against consilience is sheer folly and muzzling the fruits of consilience is the ultimate crime.

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It would be a waste of my time to fully analyze the literature on my own.  I trust the scientists working in the field who build high-tech apparatuses, take data over decades, and meticulously analyze it.  After all, the consilience they have reached is the result of extensive professional debate.  It is arrogant for citizens without expertise in a field to deny anthropomorphic climate change based on the fact that Moscow Idaho has been exceptionally cold this winter.  Policy should be based on the best evidence that science has to offer, and the scientists -- as a group -- with expertise in areas related to climate science are the ones who should be trusted by the public.


NOTE:

Global warming is a scientifically imprecise term because it focuses on the temperature increase, which is a consequence of extra trapped energy.  When light from the sun is absorbed by air, the earth's surface, and oceans, that energy is converted to heat.  Heat is simply the flow of energy in the form of motions of atoms and molecules.  Some of the energy of the warm earth is radiated through infrared light, but greenhouse gasses absorb that light, preventing it from escaping the earth's atmosphere, thus  converting it to heat.  Greenhouse gasses pass sunlight but block the infrared light that is needed for cooling, leading to a buildup of heat and thus an increase of the temperature.

The temperature increase due to a unit of heat energy depends on the mass of the object.  Since the oceans are so much more massive than the earth's atmosphere, the average ocean temperature will increase less than the atmosphere for a given amount of heating.  Since the energy imbalance driven by greenhouse gases is the key process at work, ocean and atmosphere temperatures must be combined if the effects of greenhouse gasses are to be accurately assessed.  That is why the land-ocean temperature composite is a good index of global heating.