Physics, asked by ashokaituc9730, 1 year ago

How are matter waves can travel with speed greater than speed of light in vaccum

Answers

Answered by ritikraj200490

The phase velocity of light can be faster than c (= 299 792 458 m/s), but the group velocity is c. The phase velocity is not the velocity that information or energy travels at.

Here’s an analogy. Imagine two rods almost parallel and touching at a point. As one of the rods moves, their point of intersection moves much more quickly. You can imagine that the point of intersection moves faster than light while the rods move more slowly. There is no physical object at the point of intersection.

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Jatin Rajput

Jatin Rajput, Quantum Mechanics is not flawed. If it went on strike, we would reach dark ages.

Answered Oct 11, 2016

Originally Answered: How can a matter wave travel faster than light if nothing can travel faster than light?

Matter waves are not physical waves. They have phase velocity faster than the speed of light which violates the laws of physics.

Their group velocity is smaller than the speed of light. So, matter waves have group velocity ( v < c ).

A matter wave travels with group velocity equal to ‘v’ which is also the velocity of an electron present in that matter wave. Both travel with velocity ‘v’. We can only find the probability of an electron to be found in a particular region in the matter wave.

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Phalgun Madhusudan

Phalgun Madhusudan, Lifelong student and teacher, Physics enthusiast

Answered Sep 30, 2016

Originally Answered: Is it true that Matter waves are faster than the speed of light?

In theory, the highest physically possible speed is that of an electromagnetic wave and is 2.99792458x10^8 m/s.

When it comes to matter waves, as your textbook says, you have somethings called phase velocity and group velocity. Group velocity is the velocity of a wave packet, while the phase velocity is the velocity of individual waves in a packet. The a actual, measurable velocity of a particle is the group velocity and is always lesser than that of light, in a given medium.

A very interesting thing with regard to superluminal speed of a matter wave is when a charged particle moves in a medium with a velocity greater than the phase velocity of light in that medium, it releases something like a sonic boom of photons. These radiations are called Vavilov-Cherenkov radiation or simply Cherenkov radiation.

You can read more about Cherenkov radiation here. Cherenkov radiation

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Haaran Ajgaonkar

Haaran Ajgaonkar, Completed a course on Relativity on Coursera

Answered Aug 26, 2016

Originally Answered: Is it true that Matter waves are faster than the speed of light?

Nothing can ever travel faster than light and if a body tries to do so the time in that reference would slow down such a degree that the speed limit of the light is maintained. I saw the photo attached and it says faster than em radiation and not light. They are two different things. Electromagnetic Radiations cannot travel faster than light.

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Debashish

Answered Aug 26, 2016

Originally Answered: Is it true that Matter waves are faster than the speed of light?

You might have noticed that the book mentions two velocities, The phase velocity and the group velocity, Now as you might have guessed with the word ‘group’ there are more than 1 wave associated with a matter particle, all this waves are identical apart from their phases and each one independently has a speed faster than the speed of light and hence faster than the particle itself but none of this single wave exist independently, They exist in a group and because of their phase difference they interfere to such an extent that the resultant velocity of this group of waves is exactly equal to the velocity of the particle. Or thats what i am able to recall from my high school physics lessons.

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