http://physicsoverflow.org/28736

In the light of the current warp field experiments by NASA I found this paper:

http://arxiv.org/pdf/1005.5682v1.pdf

http://arxiv.org/abs/1005.5682

Could this actually lead to the creation of exotic matter or at least strengthen the case that a warp drive, or a least a warp field is possible to create?

general-relativity vacuum gravity spacetime

asked Mar 23 in Theoretical Physics by WolfInSheepSkin (-40 points) [ revision history ]

recategorized Mar 23 by dimension10

Hi @WolfhSheepSkin,

Is this really an ArXiv paper? When I follow the link it does not look like a standard ArXiv paper. Would you mind linking to the abstract page instead of directly to the PDF?

commented Mar 23 by Dilaton [ no revision ]

@Dilaton : Alright, I updated my question.

commented Mar 23 by WolfInSheepSkin [ revision history ]

Maybe this will help

see twistor’s answes on PSE.

how far did you study. Why are you thinking about warp drives? Do you understand the basic formalism of GR and Quantum field theory?

There seems to be some amount of work concerning negative energy using casimir effect, However I don’t understand the meaning behind such a thing. I have no idea about its application to worm holes either.

Kip thorne has written papers about these possibilities.

commented Mar 26 by Prathyush [ revision history ]

edited Mar 26 by Prathyush

1 Answer

+ 3 – 0

Hey, it’s that paper that’s always referenced on the standard Eric Davis presentation on wormholes! I don’t trust that guy too much because he writes a lot about aliens and psychic powers, but anyway.

Quantum effects, as well as some classical effects routinely violate almost every energy conditions that you can throw at them. So far quantum effects have been show to be able to break the trace energy condition, the strong energy condition, the weak energy condition, the null energy condition, the dominant energy condition, the averaged energy conditions and quantum inequalities (a good review here : http://arxiv.org/pdf/gr-qc/0205066.pdf). Those are of course all theoretical, though.

Here’s a little list of various effects known to violate some of them. I’m not at home so I don’t have all the papers in mind but I included a few :

Squeezed quantum states, and generally various superpositions of number states for free quantum fields. Those can indeed be produced experimentally (they are commonly used because they are useful for high precision interferometry), but whether or not they violate the null energy condition remains to be proven (their energy can be made inferior to the vacuum state energy, but what the absolute energy is cannot be determined without being able to detect gravitational effects). For informations regarding them, quantum optics book usually contain a good amount of details on them. Also :

http://arxiv.org/pdf/0705.3003.pdf

The Casimir effect. While the Casimir effect is probably not best described by the commonly used explanation (metal plates are not perfect conductors and the Casimir is best fundamentally explained by QED loop contributions), the topological Casimir effect (where cyclical coordinates induce this) does have this explanation, and various instances of the Casimir effect (the usual one with metal plates, as well as more esoteric ones with domain walls) do seem to violate it. The same experimental problem to actually prove it applies.

Casimir effect from domain walls : http://arxiv.org/pdf/gr-qc/0205134v3.pdf

Energy density in the Casimir effect : http://arxiv.org/pdf/quant-ph/0504143.pdf

Gravitational squeezing. Various spacetimes force quantum fields into negative energy states at some points, most famously the Schartzschild metric with the Hawking radiation. Being a gravitational effect, this one cannot be tested experimentally so far.

Energy conditions using various definition of the vacuum in the Scharzschild metric : http://arxiv.org/abs/gr-qc/9604007 http://arxiv.org/abs/gr-qc/9604008 http://arxiv.org/abs/gr-qc/9604009 http://arxiv.org/abs/gr-qc/9703001

All manners of theories with interacting fields. Generally speaking, the most egreious violations of the energy conditions occur in interacting fields (which is the case for 2., 3. and 4.), because for the most part free fields are the main ones studied. In the case of the Casimir effect, it even violates the quantum inequalities, which is the one that is the least likely to be violated in general. Other examples in general are :

Scalar fields that are non-minimally coupled to curvature : http://iopscience.iop.org/0264-9381/19/19/309

Various studies for energy conditions in interacting models : http://arxiv.org/pdf/1502.01714v1.pdf

Various cheating effects. A lot of papers also make a variety of quantum fields more or less ad-hoc to study solutions. Among those are phantom fields (fields with negative kinetic energy).

In general if you want more informations about the topic I advise “Lorentzian wormholes” by Matt Visser and “Frontiers of Propulsion Science”. Don’t get your hopes up too much though. The existence of exotic matter is but one problem of all spacetime trickery and the White-Juday warp field interferometer experiment is a bit suspiscious.

answered Jun 18 by Slereah (130 points) [ revision history ]

Hi, Thank you Slereah.

commented Jun 18 by WolfInSheepSkin [ no revision ]

Are on the freenode irc physics channel??

commented Jun 18 by WolfInSheepSkin [ no revision ]