Copasetic Flow

Scroll to the bottom for background on the experiment. Checked that the pole faces of the yoke magnet retract fully leaving enough room for the glass Dewar.  The poles do retract far enough, but there is a trick to it.  The rotator that advances and retracts the pole piece should have two metal collars associated with it.  On the side I initially tried to adjust, one of the collars was missing and the pole would not move.  When I moved the second collar to that side of the magnet, the pole piece moved after applying a little bit of force Here's how it works  The collar the handle protudes from is threaded on the inside.  It turns on the threads that are visible and are attached to the pole piece.  If the second collar is in place, then the torque created by the handle is applied to the threads of the pole piece and it slides back and forth through the treads of the handled piece along a small rail at the bottom of the threaded pole.  A...

My review of the material I mentioned yesterday [1] paid off pretty quickly.  Dr. Hirsch is quick to point out that one of the key differences between his 'hole theory of superconductivity'[4] and the more typical explanation of Cooper pair formation is that his theory predicts kinetic energy lowering after two holes in an energy band pair as opposed to the usual potential energy lowering after two electrons pair . While reading Hirsch's articles, I didn't remember ever coming across kinetic energy lowering pairing before.  It turned out that I had read about it in Dr. Likharev's notes , (see section 2.6, 'Coupled Quantum Wells'), but without an immediate application for the information, I promptly forgot it. Here are the basics 1.  Crystalline materials, (like superconductors, or semiconductors), in which electrons reside can be very roughly modeled as repeated delta function wells, (picture 1)[2] where the delta functions represent the potentia...

I'm reading through the following in preparation for writing a (hopefully) simplified summary of the electron-hole theory of superconductivity.  For those who would like to follow along, each of the references below i a great resource targeted at different experience levels. 1.    +Jonah Miller 's article on band structure as it relates to how materials conduct electric charge [1].  This is a great starting point for the lay-audience.  Jonah is great at explaining physics at any level by the way!  He recently walked Elaine and I through the rudiments of lattice gravity calculations over alcoholic slushies at the  +APS Physics  April meeting. Photo Credit  +Jonah Miller   2.  Dr. Likharev's, (of Stony Brook University), Quantum Mechanics I notes relating to the same topic, but from the point of view of Bloch's theorem.  These are targeted at the physics graduate student reader.  His notes show how the unallowed r...

What follows is an explanation of a phrase that Hirsch uses in most of his papers, “hole-electron asymmetry of condensed matter”.  The explanation was adapted from one of Hirsch’s papers[1], that can be found on arxiv as well as Phys. Rev . B. Here’s a more complete derivation of the London penetration depth from the London Moment field equation mentioned below. [2] Hirsch frequently refers to the ‘hole-electron asymmetry of condensed matter’.  In the article entitled “Electron-hole asymmetry and superconductivity”, he provides a nice picture of exactly what he means by this phrase.  I adapted the explanation for a presentation I’ll give soon on the H-ray theory.  The slides follow.  A more complete and texty explanation can be found at the link above.  The text that follows below is the very rough draft of some of the vernacular for the presentation.  For those who are die-hard fans of watching people fumble with practice presentations, I've also...

Congress to vote on STEM funding for NASA and the NSF today The House of Representatives is voting on science funding of both NASA and the National Science Foundation, (the guys that pay my paycheck), today.  If you like to read the bill, it can be found at:: http://docs.house.gov/meetings/SY/SY15/20140313/101907/BILLS-113HR4186ih-HR4186FrontiersinInnovationResearchScienceandTechnologyActof2014.pdf If you'd like to contact your Congressperson to help out, +APS Physics  has setup a handy 'find your congressman' app at  http://www.congressweb.com/apspa I called my representiative, Bill Flores and spoke with a very helpful and friendly staffer.  No fuss, no muss. If you wonder what to say, the APS has ideas for you, read on for a sample email and phone call script: Sample E-mail Dear Representative X, My name is [YOUR NAME], and I am a physicist from [City, State] and a constituent of [Rep. Congressperson]. I work at [Institution] in [City, Stat...

Meetings, Magnets, and Special Relativity Spent the morning attending a meeting and getting to do just a tiny little bit of special relativity research, regarding proper acceleration in the instantaneously moving rest frame.  The rest of the day was spent debugging, first the liquid nitrogen Dewar, and then the leak detector.  The leak detector is still not up to snuff.  Prep work was done for lifting the magnet that will supply the quenching field for the superconducting samples. New to these posts? The hole theory of superconductivity, a BCS compatible modle, predicts that when a superocnductor is brought back to its normal state quickly, it will emit x-rays.  We plan to experimentally verify this or set a new lower limit for its detection.  Scroll to the bottom for more complete information of what this physics experiment is about and what we hope to achieve. Relativistic range work: Reviewed and followed Brehme’s derivation of proper accelerati...

Superconductor Quenching Magnet Cooling Supply Work The magnet that will be used to quench the superconductor in our experiment is water cooled.  So is its power supply.  The water chiller that will provide the cooling was checked out and filled.  The plumbing to the supply was constructed and tested.  Two of the water lines required SwageLocks rather than Parker fittings to prevent leaks. The superconducting sample is to be placed in a liquid helium Dewar during the experiment.  Work is being done to check the status of a second Dewar that can be used as a backup to the first.  At present, the leak detector for this work is not functioning properly.  Some time was spent on debug of the system with no conclusive answers found. New to the game?  Scroll to the end for background on what this is all about. Leak Detector Debug Looking into why the leak detector no longer pulls down to < 10^-2 Torr quickly, (at all?).  Cleaned th...