Is Imaginary mass = Negative mass. I need your help...

[why06]

Hello Scienceforums.net,

 

I am why06 from SDC (space.com)

This may sound a little weird but I am seeking help from many different scientific communities to answer a question that is baffling us at SDC.

About three weeks ago I started a thread in SDC in the Space Science & Astronomy section. It was about a possible substitute for dark energy and matter dealing with tachyons. I am not here to discuss this though. No this hypothesis can be saved for another time. My question is one dealing with the physics of tachyons themselves. All of the minds put together at SDC could not figure this question out but perhaps YOU can....

 

Question:

Tachyons have imaginary mass. Now is imaginary mass real? If so is it positive or negative.

 

The question is not as easy as it seems. But we would really appreciate it if someone of enough knowledge pertaining to this ssubject can answer this question. A warning to those who try to solve the problem with a quick link...... WE at SDC have been discussing this isue for 11 PAGES of 20 post pages. There are approx. 200 Posts on this subject!! We have simply found that their are to many discrepencies in internet sources to find a true answer.

 

The original thread at SDC: Dark Energy and Tachyons

The same question asked at BAUT: Imaginary Mass = Negative mass?

 

 

Thankyou and Goodluck with this baffling question.

 

If you would like me to post my hypothesis or need to ask me a question on the subject Post it or PM me at any of the three sites.

why06 out:cool:

[insane_alien]

no, imaginary mass is not real. its the foundation of complex numbers in mathematics, it is nether negative nor positve.

 

If you think back to when you were learning maths for the first time, you probably had a 'number line' or something similar. If you didn't its a line with bits marked of for each of the numbers. imaginary numbers can be put on to this by using another axis perpendicular to the numberline. a complex mass would consist of a real part and an imaginary part, maybe. we don't even know if its possible so we can't make predictions about it.

[why06]

Here you do not fully understand the question.

 

Tachyons have imaginary rest mass. There for they would seem to have real mass to a STL observer. Now I am wondering weather that mass would be positive or negative. Currently we are leading to the side that tachyons may have negative mass, but we have not got a flat out answer yet. If we can not reciev one. I will infer the answer to the best of my abilities.

 

Keep posted about the conversation on other sites.

 

If someone trained in physics could give us a definitive answer that would be great. Thankyou

 

why06 out

[foodchain]

Well I am not trained in physics but as far as I know the item in question has not even been verified to exist in nature.

 

"It has been proposed that tachyons could be produced from high-energy particle collisions, and tachyon searches have been undertaken in cosmic rays. Cosmic rays hit the Earth's atmosphere with high energy (some of them with speed almost 99.99% of the speed of light) making several collisions with the molecules in the atmosphere. The particles made by this collision interact with the air, creating even more particles in a phenomenon known as a cosmic ray shower. In 1973, using a large collection of particle detectors, Philip Crough and Roger Clay identified a putative superluminal particle in an air shower, although this result has never been reproduced."

 

Quoted from http://scienceworld.wolfram.com/physics/Tachyon.html

 

So I would have to ask if you are attempting to answer a question in say reality of in mathematical models, and if its in model form then you really do need someone grounded in physics to help you, and I think the answer could probably go in the running for a Nobel prize actually.

[swansont]

[math]E = \gamma m_0c^2[/math]

 

Gamma is imaginary and also negative. So it all depends on what you want — if the energy is to be real and positive, then the rest mass must be imaginary and positive. If you want a real rest mass, that makes the energy imaginary and negative, or you could have negative and real rest mass, giving you an imaginary and positive energy.

 

None of that currently has any physical meaning.

 

I think that in some high-energy/particle physics, the relevant tems are mass^2 and energy^2 in some of the equations, but I think you still end up with a sign problem.

[ajb]

One way to avoid the issue of an imaginary mass is to modify the mass shell condition

 

[math]E^{2} + m^{2}= p^{2}[/math]

 

By doing so we now have a positive mass squared and so no issue about imaginary mass. Doing this does not effect any of the properties of tachyons.

 

In quantum field theory tachyons are usually associated with a poor choice of vacuum when doing pertubation theory. That is they can be removed from the spectrum by making another choice. In string theories, this approach is more difficult and is the subject of "taychon condensation".

 

Tachyons as well as generically being unstable, would produce some disturbing effects notably if they are charged. As they interact with the electromagnetic field they lose energy due to Cherenkov radiation. As they lose energy they accelerate and lose more energy in a run away process! This process could produce infinite energy! The same thing would happen in a gravitational field.

 

So, it looks like QFT should forbid tachyons even if relativity does not.

[ajb]

I should also say that some of the original papers on the subject can be found on George Sudarshan's website. He was one of the first people to investigate faster than light particles from a modern view point.

[why06]

Thankyou by the way I went t the library and did some research of my own. It urns out tachyons have imaginary rest mass because mass squared is less than zero this means tachyons have negative mass? I think.

Also the effect you describe can happen only when tachyons are charged.

[ajb]

It turns out tachyons have imaginary rest mass because mass squared is less than zero this means tachyons have negative mass? I think.

I don't understand what you are saying. First you said that Tachyons have imaginary mass then you say they have negative mass.

 

I think that Tachyons have imaginary "rest mass". (unless you modify the mass-shell condition as I suggest). This is not a problem as we can never measure the rest mass of a Tachyon. This is becasue as we move slower than light we can never share a rest frame with something moving faster than light. The same is true for photons, we can never share a rest frame with them and so we cannot have a good notion of rest mass for a photon, i.e. we have the "strange" m = 0.

 

So I would not get too hung up on the notion of an imaginary mass. We never observe it. The "mass" of a tachyon should be considered as a parameter in the theory and you should be very careful about attatching a physical notion to it. (This is what one should do when dealing with QFT anyway as we have issues of renormalisation to contend with before we can attach any physical significance to parameters).

 

 

 

 

Also the effect you describe can happen only when tachyons are charged.

Which is what I said.

[why06]

What do you mean....

The "mass" of a tachyon should be considered as a parameter in the theory and you should be very careful about attatching a physical notion to it.

 

I have thoroughly explained that tachyons have imaginary rest mass and hence negative mass in reality in this thread. http://uplink.space.com/showflat.php?Cat=&Board=phenomena&Number=658235&page=0&view=collapsed&sb=5&o=31&fpart=11

 

 

And for Cherenvok radiation..... Yes you did say that, but you never said they were charged

 

why

[ajb]

Go away and learn some QFT and you will know what I mean.

[fredrik]

Tachyons have imaginary mass. Now is imaginary mass real? If so is it positive or negative.

 

IMO, the preferred way to resolve this question should be to take several steps back and start question and rectify meaning of basic terms and define what the reference or starting point of the whole reasoning is and what we are getting at. Ideally the starting points should be at least in principle observable quantities, otherwise I don't know what we are talking about here?

 

Usually mass is a parameter of a model or theory, which is defined by relations, often involving yet OTHER parameters of the same theory. This is why I think many concepts in physics only have a relational meaning and are entangled up. If one starts to twist the meaning of things out of context one need to decide how all the relations are supposed to behave during this twist so that the basic demands of consisteny of the theory remains.

 

Clearly speed and change are entagled up with alot of things like causality and locality. Mass is usually entangled up with energy and momentum which is also just relationally defined and not very clear either, as time is usually involved there too.

 

Also these "relations" depends on what theory you are working with. If you are trying to expand some existing theories, then the way of modification must be regulated. How does is consistency preserved during the adapation?

 

/Fredrik

[why06]

Nice answer ms. penguin

Now lets ask ourselves did that really help any. Did you learn what you have just to keep it to yourself. I doubt your as smart as you think. I still dont know QFT means. You see that is what we call jargen and not only jargen but abbreviated jargen. And the truth is that I might actually understand what your talking about if you would stop being a smart. And spen the extra FIVE seconds of your God given times to spell out the words QFT for me. Please prove your intelligence to the world....

[fredrik]

QFT just stands for Quantum Field Theory, and is formalism for quantum mechanics on fields where usually the quanta of fields are interpreted as particles (field-quanta). This is unlike the schrödinger quantum (nonrelativistic) mechanics devised to be consistent with special relativity. For example the quanta of the electromagnetic field is the photon.

 

http://en.wikipedia.org/wiki/Quantum_field_theory

http://plato.stanford.edu/entries/quantum-field-theory/

 

/Fredrik

[why06]

Thankyou Fredrik,

I like the way you think & appreciate the help. Now I would like to post a hypothesis I have do you know a place where I can do this? Well better not be lazy... I suppose I could look.

[fredrik]

I have not searched for other forums, I just came here myself not too long ago. I think if you want comments on an idea you have, the most important part to start with is to try (even though it's hard) to explain what your purpose is. Sometimes psychology is involved too. To get a comment you'd want to explain what you are doing.

 

For example, do you propose reinterpretation of something? Do you propose that some current theory is wrong?

 

To speak for myself, I was not entirely clear on what you where suggesting.

 

"Tachyons have imaginary mass. Now is imaginary mass real? If so is it positive or negative."

 

Is your hypothesis that tachyons have imaginary mass? In order to understand the question tachyons must be defined in a way that connects in to reality. And does imaginary mass make sense at all? It's hard to understand exactly what your idea is... until I understand that it's hard to comment properly. I can comment what I think, which I did.

 

What is your starting point, for posing the question? Are you thinking in terms of experiments or are you thinking in terms of "toying" with formulas in special relativity. Try to define the terms more from your point of view. Ie. what is your idea of mass, and what is your idea of tachyons. What principles to you believe in? I feel some things is floating here. And the first step before making hypothesis is to apply some order of concepts.

 

One obvious question is how to you consistently measure or relate to superluminal speed? I'm not saying there is no way to do it here, I'm just saying that since it's speculative in nature, there may be different views on it. And I think the chose view may matter to your question.

 

/Fredrik

[why06]

I posted it on this site under physics/ astronomy.

 

However this thread was not started to stat my hypothesis. I was simply asking a question based on the physics of tachyons. Beleive it or not it is very hard to find imformation on hypothetical particles. And most books defraign [i know I spelled that wrong] from talking about the negative mass properties of tachyons. I really just want to ALL the physics of a tachyon. Or at least what the are hypothesized to be...