Q: Can Matter Be Converted to Energy with 100% Efficiency?

[jonnyk]

Hi everyone,

Somewhere I've heard of a special type of laser which when it strikes matter could convert near 100% of it into energy, the laser's energy being insigificantly small as compared to the output thus achieving ~100% efficiency? Is this a way or is there any other means to achieve this without having to use anti matter? Thanks.

 

[mathman]

What you've heard doesn't sound right. Could you give a specific reference?

The only serious use of a laser for mass to energy conversion is laser fusion, but that fuses light nuclides into slightly heavier nuclides, where the mass difference is converted to energy.

 

[Stonemason89]

Converting 100% of matter into energy, without the use of antimatter, would likely be impossible due to conservation of baryon number and lepton number. The only way it could be possible would be if there were interactions that could violate conservation of B and L; none have been discovered yet. It's possible that they could exist (the X and Y bosons, if they exist, may violate B and L conservation), but it doesn't seem likely that they could be stimulated with a laser, unless the laser was at EXTREMELY high energies, corresponding to the X and Y boson masses, which would probably be near the TeV scale. No such laser has been developed yet, and it may be impossible to build such a laser.

Fusing light nuclei into heavy nuclei, as mathman said, would convert a small portion of the mass into energy, but it would be nowhere close to 100%.