Next Big Future - Latest Comments in Repulsive Casimir Force: Casimir-Lifshitz force experimentally verified

Re: Repulsive Casimir Force: Casimir-Lifshitz force experimentally verified

asaf oko — Fri, 27 May 2011 07:16:48 -0000

The first discovey of the repulsive force at long distances was not by Munday et.al. Look into the references in the Nature publication, reference number 15: "Superlubricity Using Repulsive van der Waals Forces" from 2007 by Feiler et. al. showed it. they didn't name it Caisimr... but simply repulsive VAN-DER-WAALS forces. For me the Nature article is no more then a copied experiment with different titles. They don't even explain well the nature of the repulsive force, while Feiler theoretical expplanation is much more clearer.

Re: Repulsive Casimir Force: Casimir-Lifshitz force experimentally verified

GoatGuy — Fri, 11 Feb 2011 17:20:33 -0000

Perhaps so! I agree - I would have been surprised if they were nonlinear forces. Truth is that like magnetic fields seem pretty magical - because there's "nothing" between two magnets that keeps them separate except that magnetic field pushing them mutually away. "There's got to be a way to harness that for creating energy!"... well, no. Same with Casimir. No. All circular integrals of work done in the presence of any linear field have a recoverable energy cost of precisely zero. Not close, or for certain paths, or with any other caveat. Zero, in all cases, under all conditions, except when external forces either add or change the energy dynamic itself.

(You need that caveat in order to account for how electric motors and any other electromagnetic "tool" works.)

<small>G O A T G U Y</small>

Re: Repulsive Casimir Force: Casimir-Lifshitz force experimentally verified

Brett_Bellmore — Thu, 10 Feb 2011 20:20:53 -0000

"In a series of discussions with researchers actively looking into all of the various Casimir forces, the net 'problem' with the Casimir force (which is NOT a problem, but just a physics based reality) is that rather like our macro-scale Maxwell's Laws that completely describe electromagnetics, the Casimir forces are also linear through all path integrals. "

Well, of course they are: At their root, the Casimir forces ARE electromagnetic forces.

Re: Repulsive Casimir Force: Casimir-Lifshitz force experimentally verified

nanoqed — Tue, 13 Jan 2009 19:17:33 -0000

Casimir extended the microscopic van der Waals force between atoms in a gas to the attraction between macroscopic bodies in a vacuum. However, recent experiments have suggested that the Casimir force can be changed from attraction to repulsion by immersing micron sized gold and silicon structures in liquid bromobenzene.

But this experiment not only falsely presupposes the Casimir force exists, but then extends that falsity to conclude the attractive Casimir force can be changed to repulsion. Indeed, the Casimir force is shown to not exist because Casimir did not conserve the EM radiation in the gap between parallel plates, for if he would have, Casimir would have found the frequency of the EM radiation increases by QED as the gap decreases because the EM energy in the gap must be constant. The gradient of the constant EM energy with respect to the gap therefore vanishes and there is no Casimir force. See www.nanoqed.net at link "Casimir"

If there is no Casimir force, what then is being measured?

Since all measured Casimir forces only occur at gaps less than 200 nm, the EM radiation in the gap reaches VUV levels and the plates charge oppositely by the photoelectric effect. Therefore, the attractive force measured in Casimir experiments is electrostatic caused by the QED charging of the plates by VUV radiation. The usual attractive QED induced electrostatic force of oppositely charged gold and silicon structures is changed to repulsion upon immersion in bromobenzene because the latter is an electron scavenger that alters charge distribution.

Re: Repulsive Casimir Force: Casimir-Lifshitz force experimentally verified

GoatGuy — Mon, 12 Jan 2009 12:49:59 -0000

Mayonnaise. That was the first material where the Casimir repulsive force was observed. The intrepid researcher was looking to figure out why mayonnaise is such a durable suspension, and moreover, why mayonnaises are largely nonlinear rheodynamic fluids. The Casimir repulsive force figures centrally into the dispersion parameters of the oil nanospheres that constitute the mayonnaise suspension.

In a series of discussions with researchers actively looking into all of the various Casimir forces, the net 'problem' with the Casimir force (which is NOT a problem, but just a physics based reality) is that rather like our macro-scale Maxwell's Laws that completely describe electromagnetics, the Casimir forces are also linear through all path integrals.

Analogous to Gauss's law for magnetism ( del-B equals zero ... in differential form, or circ-integral B dA equals zero ), which states that the integration of force or flux change over any closed path in a magnetic field yields precisely zero net power, the Casimir forces also appear at all scales to be similarly closed to either energy consuming or energy delivering paths.

NET? Interesting research, and there will be many 'things' that will come from it. But I'm not holding great hopes for a new kind of space propulsion. (One of the other leading candidates is unidirectional hyperpower laser propulsion... where the orders of magnitude clearly could deliver results, but the requirements for power-to-propulsion production remain almost fictionally distant.)

GoatGuy