# Ask-a-Physicist by Topic

## Quantum Mechanics

It looks like they are looking for positive mass particles at the LHC at CERN. Isn't it logical that there are negative-mass "anti-particles"? Does the LHC have the capability of measuring negative mass?

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Is there a particular range of frequencies at which parts of the human body (or the
human body overall) normally vibrates? Because in an episode of the sci-fi TV series
*Fringe*, they claimed that they could figure out if one character was from this universe
or a parallel universe by measuring the frequency at which he was vibrating.

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Hello, I am trying to figure out the practice behind the experiment I've heard about in a National Geographic documentary, so please help me a bit.

How do they generate entangled particles in the lab (photons)? Also, how do they make photons to interact with each other and what kind of interaction do they make?

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My 7 year old son Ben (who is sitting next to me now) has recently become interested in how small things can be. He is not convinced that nothing can be measurably smaller than a Planck length because whatever is Planck sized can always be divided into something smaller.

He thinks perhaps Planck lengths can be divided into energy beams that then become infinite.

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Does Einstein's relativity of simultaneity mean that two events cannot be simultaneous or that we cannot prove that two events occurred simultaneously?

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I have a question about waves and particles. Since waves and particles seem to be somewhat interchangeable at the subatomic level, at what wavelength does the wave / particle duality stop?

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In the proton-proton chain reactions which happen, for instance, in our Sun, two protons collide and form a proton and a neutron. However, this just blows my mind.

What is the mechanism by which a proton simply loses its charge, becomes slightly more massive, and turns into a neutron?

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If the recent result of the tests of the speed of the neutrino are validated by other research groups what are its implications for the standard model of particle physics as it has been described to date?

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There seems to be a lot of debate about how accurately CERN measured the departure of their neutrinos. Could they not aim them at some other neutrino detector in the world and just use the difference in distance and time from the readings in Italy as this would eliminate the error in not knowing exactly when the neutrinos left CERN?

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When carrying out the double slit experiment using electrons or buckyball molecules, do the particles have to be traveling at near light speed velocities to produce an interference pattern?

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