# May I suggest an experiment concerning negative energy?

1. Jun 15, 2011

### Negeng

Sometimes to understand things I need to come up with ideas and have them shot down.

This is what I am doing here.

I have been informed that the Cashmeir effect may not be due to negative energy so I have an idea for an additional experiment. Suppose we were to make a "box" with little "Pockets" and these "pockets" simulate the cashmeir effect by having the walls of the pockets be a very small distence from each other. If the cashmeir effect is indeed due to negative energy we would expect the box to weigh less than the materials that make it up, because the negative energy in the pockets would have negative mass. On the other hand I would assume this apparent decrease in mass would be very small, on par with weighing a photon. Futhermore gravity would most likely pull on the negative energy like it does postive energy so weighing the box would not be a simple matter of just putting it on a super acurate scale.

I would love to hear all kinds of comments on this possible experiment.

2. Jun 15, 2011

### Demystifier

Yes, that would be the main obstacle to perform the measurement.

3. Jun 15, 2011

### SpectraCat

First I guess you had better define what you mean by "negative energy". It is not at all clear to me why the Casimir effect (note spelling) should result in any mass decrease at all, even a very small one. Basically, whatever the interpretation, the Casimir effect is just a correction of the zero-point energy, based on what we would expect it to be in the absence of the effect.

If you put two methane molecules close together, and you don't know about, or neglect to consider van der Waals interaction, then you will be surprised when you find their zero-point energy is lower than you were expecting it to be. The Casimir effect is no different.

[EDIT] I should say that there will be an INCREDIBLY tiny mass change due to the extra binding energy in the system. It was so small that I didn't even notice it in my analysis ... perhaps the OP would like to calculate the size of the mass change?

4. Jun 16, 2011

### Negeng

I know the amount of negative energy within my suggested pockets would be small (if it's even there at all), but how small exactly? Is there an equation that would predict the amount of negative energy for any given dimensions in the pockets?

To my understanding mass and energy are interchangable so one could have say 1 killogram of energy. Therefore if my understanding of negative energy is correct then you could have
-1 killogram of negative energy and a negative amount of mass could exist within the two plates that creates the Casimir effect. Please correct me if I have misunderstood something.

5. Jun 16, 2011

### danR

I'm not really clear on the geometry of the pockets and box, but that's not important. The Casimir effect depends on the exclusion/displacement of non-resonant (posited) vacuum energies, not on their disappearance. Those displaced components will appear elsewhere in the box, presumably inside the material walls forming the excluding pockets.

For an analogy, we can make box containing some cellular substance, such as an aerogel and coat the inside of the cells with a 'getter' such as cesium. The cesium sucks up all the oxygen and leaves the nitrogen and argon, but the whole box weighs the same.

6. Jun 17, 2011

### Negeng

Is there any chance the heisenberg uncertainty principle would allow the diplaced components to be outside the box?

Last edited: Jun 17, 2011
7. Jun 17, 2011

### danR

Yes, but it would allow all components of the (conjectured) vacuum energy of both a pocketed and unpocketed box of identical mass to be outside the box anyway. IMO. At this point we need an expert to comment more precisely.

8. Jun 18, 2011

### Negeng

Well in the mean time I will draw people's attention to this article, http://xxx.lanl.gov/abs/gr-qc/9901074

It decribes an attempt to seprate positive energy from negative energy. The authors claim it can be done, but there are strong restrictions. Most notably any pulse of negative energy must be close to a pulse of postitive energy or the postive pulse must be much larger the the negative pulse. I leave it to you and others for futher interpertation.

9. Jun 18, 2011

### danR

That isn't quite what I see in the abstract. The bigger the positive and negative pulse, the closer they must be in time. Their earlier paper, they say, finds an asymmetry: the greater the separation (in time? that's what the previous context would suggest.), the greater the positive pulse than the negative one.

10. Jun 19, 2011

### Negeng

Yes...that's what I meant.

11. Jun 19, 2011

### SpectraCat

Well .. that is a theory paper, so I wouldn't characterize it as an "attempt to separate positive energy from negative energy", but rather as an attempt to prove that it can be done in principle. I am not sure if experimentalists even know how to generate such a "double-pulse" of positive/negative energy. I thought they were just types of vacuum fluctuations ...

12. Jun 19, 2011

### danR

I don't think realizing the theory in an experiment would help in the design of the Casimir box in any event. It would certainly involve measuring events in a small volume of space (and time). Your box would be large static thing which probably would not need any pulses measured or generated with respect to it. We would be measuring for bulk mass deviations.

13. Jun 19, 2011

### Negeng

I don't think the general idea of quntam intrest and the Casimir box (I love that term by the way)need always be seprate. If quntam intrest is indeed true then it means there could be some method of moving the displaced postive energy outside of the box while keeping the conjectured negative energy in it; the catch is we would not be able to do it for very long especially since we would need to isolate enouph of the casimir force to measure it's mass.

On the other hand if the double pulse experiment were conducted it would defeat the purpose of the casimir box; we only need one experiment that isolates the suposed negative energy after all.

14. Jun 19, 2011

### danR

So you just want the negative energy thing tested for reality, the Casimir box isn't necessary. Probably a lot of people would like to see that, but as SpectraCat suggests, it might be hard to test according to the paper.

15. Jun 24, 2011