Particles with complex number mass.

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Discussion Overview

The discussion revolves around the theoretical concept of particles with complex number mass, particularly focusing on tachyons, and the implications for Lorentz transformations and quantum field theory. Participants explore the physical interpretations and mathematical foundations of these ideas, considering both classical and quantum perspectives.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested

Main Points Raised

  • One participant suggests that tachyons, which are theorized to have imaginary mass, could lead to modifications in Lorentz transformations to accommodate complex mass particles.
  • Another participant clarifies that Lorentz transformations pertain to coordinate transformations and do not directly involve particle properties.
  • A different viewpoint emphasizes that in quantum field theory, particles correspond to states in a Fock space, and the invariance group determines the types of particles allowed, implying that Lorentz transformations are relevant to particle classification.
  • Some participants argue that while mass squared is a real quantity for ordinary and tachyon particles, complex mass would imply a non-real mass squared, which may not be physically meaningful in classical physics, though it could have interpretations in quantum physics.
  • One participant proposes that complex mass could be understood through the relationship mm* = |m|^2, suggesting a way to make sense of complex mass in a quantum context.

Areas of Agreement / Disagreement

Participants express differing views on the implications of complex mass and its compatibility with Lorentz transformations, with no consensus reached on the physical meaning or validity of complex mass in either classical or quantum frameworks.

Contextual Notes

There are unresolved questions regarding the physical interpretation of complex mass and its implications for mass squared as a non-real quantity, as well as the dependence on the definitions of the invariance groups in quantum field theory.

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I was thinking in the bus, we have theoretically speaking particles such as tachyons with imaginary number for their mass. These particles if they exist always run at speeds higher than c.

My question is has anyone thought of modifying perhaps Lorentz transformations to give us the possiblity of a complex number mass' particles.

Well, you might ask what does the imaginary part of the mass will signify, well this is really a physical interpretation I rather not go here yet.
 
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The Lorentz transformation does not involve any particle.
It deals with the transformation of coordinates.
Of course it can be applied to the coordinates of some particle, but the properties of the particles play no role, only the coordinates matter.
 
Well, actually in any quantum field theory the particles are represented by states in a fock space, and there is a different specie of particle for any infinitedimensional representation of the Poincarè group...
In fact, Lorentz transformations do fix which kind of particles are allowed.
If the invariance group of the theory would be something other than $SO(1,3)$ then other particles would be preticted.
 
The relevant quantity is not the mass, but the mass squared. It is a real quantity for both ordinary and tachyon particles, which is why they make sense. Complex mass would correspond to mass squared which is not a real quantity, so it would not make sense physically. At least not in classical physics.

In quantum physics it might make sense because complex mass (and mass squared) would be a property of the wave function, which, of course, does not need to be real.
 
Demystifier said:
The relevant quantity is not the mass, but the mass squared. It is a real quantity for both ordinary and tachyon particles, which is why they make sense. Complex mass would correspond to mass squared which is not a real quantity, so it would not make sense physically. At least not in classical physics.

In quantum physics it might make sense because complex mass (and mass squared) would be a property of the wave function, which, of course, does not need to be real.

Well, you can take its mm^* = |m|^2 to make sense of it.
 

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