Undergrad Can Particles Defy Time by Reaching Below Absolute Zero?

[BobbaD]

Could a particle be sent back in time on it's world line? Time is defined by events, but at absolute zero, there is no movement or vibration of a particle - does not time cease to pass then at absolute zero for the particle? If the particle was somehow brought below absolute zero, could it be sent back in time? The working assumption is that a particle cannot be brought to absolute zero or below, but what if we step outside that framework for a moment?

 

[DennisN]

Hi BobbaD, and welcome to PF!

The working assumption is that a particle cannot be brought to absolute zero or below

I assume you mean a thermodynamic system can't reach absolute zero due to the third law of thermodynamics.

but what if we step outside that framework for a moment?

For what reason? From falsehood, anything follows...

 

[Vanadium 50]

but at absolute zero, there is no movement or vibration of a particle

That is not true.

does not time cease to pass then at absolute zero for the particle

No.

If the particle was somehow brought below absolute zero

It can't.

could it be sent back in time?

No.

 

[Dale]

does not time cease to pass then at absolute zero for the particle?

No. There is no theory of physics that predicts that time stops at absolute zero. In fact, the SI second is currently defined for cesium atoms at absolute zero, so quite the opposite is true: not only does time not stop at absolute zero, it is actually most accurately measured at absolute zero.

 

[Drakkith]

Time is defined by events, but at absolute zero, there is no movement or vibration of a particle

Not true. At absolute zero a system of particles simply occupy their ground states. In a metal, for example, the electrons still have momentum even in their ground states.

Also note that defining the temperature of a single particle is questionable, so trying to ask about what happens at absolute zero for a single particle doesn't really get you anywhere. A low density gas can have plenty of atoms in their ground states even though, as a whole, the gas can be quite hot.

Could a particle be sent back in time on it's world line?

No. Absolutely not.

Time is defined by events

Not really. Time passes just a well for a lone particle in its ground state as it does for a collection of particles in an explosion.

The working assumption is that a particle cannot be brought to absolute zero or below, but what if we step outside that framework for a moment?

Then you leave the realm of useful, predictive knowledge and enter the realm of 'let's make stuff up'.