Tachyons and imaginary numbers?

[BadgerBadger92]

https://www.scientificamerican.com/article/what-is-known-about-tachy/

How do tachyons have mass of a square root of a negative number? I thought this was not mathematically possible?

 

[BadgerBadger92]

Excuse me, I meant “imaginary” numbers

 

[DaveC426913]

not mathematically possible?

Well of course it's mathematically possible; that's what imaginary numbers are.
Do you mean how is it physically possible?

 

[BadgerBadger92]

Well of course it's mathematically possible; that's what imaginary numbers are.
Do you mean how is it physically possible?

Yes, but also on videos (maybe not a good source) they said it’s impossible to get the square root of a negative number

 

[DaveC426913]

Imaginary numbers are employed regularly in applied physics in areas such as circuitry and signal processing, so "imaginary" isn't really imaginary. It's useful concept that models some real-world phenomena well.

Apparently, it also models hypothetical tachyons well.

 

[PeterDonis]

on videos (maybe not a good source)

No maybe about it. Normally we would ask for a specific reference, but in this case there's no point. You shouldn't be trying to learn physics (or math, for that matter) from random videos.

 

[DaveC426913]

Yes, but also on videos (maybe not a good source) they said it’s impossible to get the square root of a negative number

Well, they'd be wrong*.

The square root of -1 is i.

*not really wrong - it's all about context. In vanilla math, one can't do it - but that's because one hasn't been introduced to imaginary numbers yet.

 

[BadgerBadger92]

No maybe about it. Normally we would ask for a specific reference, but in this case there's no point. You shouldn't be trying to learn physics (or math, for that matter) from random videos.

I’ve been learning a lot of math on YouTube, but I’m thinking about just buying books for now on

Sorry if I’m bothering you guys

 

[DaveC426913]

I’ve been learning a lot of math on YouTube, but I’m thinking about just buying books for now on

Sorry if I’m bothering you guys

It is no bother. You are asking questions. That's a good thing.

 

[PeterDonis]

https://www.scientificamerican.com/article/what-is-known-about-tachy/

Unfortunately this article looks to me like another example of why Scientific American is no longer reliable as a layman's source of information (and hasn't been for quite some time--I stopped my subscription a couple of decades ago). Neither quantum tunneling, nor correlated measurement results on EPR photons, are examples of anything traveling "faster than light". The article headline is basically click bait.

The abstract of the actual paper referenced in the article is here:

https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.77.1254

Key phrase: the "tachyonlike excitations...do not violate Einstein causality". That means nothing is actually traveling "faster than light" (and it also means that whatever is actually happening can be modeled without having to use any actual tachyons with imaginary masses).

 

[BadgerBadger92]

Unfortunately this article looks to me like another example of why Scientific American is no longer reliable as a layman's source of information (and hasn't been for quite some time--I stopped my subscription a couple of decades ago). Neither quantum tunneling, nor correlated measurement results on EPR photons, are examples of anything traveling "faster than light". The article headline is basically click bait.

The abstract of the actual paper referenced in the article is here:

https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.77.1254

Key phrase: the "tachyonlike excitations...do not violate Einstein causality". That means nothing is actually traveling "faster than light" (and it also means that whatever is actually happening can be modeled without having to use any actual tachyons with imaginary masses).

Yeah I’m starting to learn that the hard way. Good news however, I’ve been pushing myself mathematically. When I get enough money I will be buying “Algebra and Trigonometry” by Blitzer. It’s a college textbook so I assume that it will be a great source

 

[BadgerBadger92]

It is no bother. You are asking questions. That's a good thing.

Thank you. Just I’m not very “popular” around here.

 

[Vanadium 50]

I’m not very “popular” around here.

You can change.

• For example, you should select appropriate levels for you threads, which in your case is B. Pretending you know more than you do helps nobody.
• You can respond to the threads you start, not just half of them.
• You can think about what people are saying before replying: - your replies took 0, 1 and 5 minutes. If people spend time posting replies that you don't consider, of course they are going to be unhappy with you. A natural conclusion is that you don't want to put in the effort to learn.
• You might think about your avatar. You might think you are another Einstein, but that doesn't mean everybody does.

 

[BadgerBadger92]

You can change.

• For example, you should select appropriate levels for you threads, which in your case is B. Pretending you know more than you do helps nobody.
• You can respond to the threads you start, not just half of them.
• You can think about what people are saying before replying: - your replies took 0, 1 and 5 minutes. If people spend time posting replies that you don't consider, of course they are going to be unhappy with you. A natural conclusion is that you don't want to put in the effort to learn.
• You might think about your avatar. You might think you are another Einstein, but that doesn't mean everybody does.

I like photography and it’s my favorite photo of Einstein.

 

[PeterDonis]

Thread closed for moderation.

 

[PeterDonis]

After moderator review, the thread will remain closed as the OP question has been addressed.