In a pair of papers printed within the journal Physical Review Letters, a staff of MIT physicists has proven that the neutrino laser — an idea proposed only a yr in the past — can not really be constructed, regardless of how superior the expertise turns into.
In 2025, B.J.P. Jones & J.A. Formaggio devised an concept for a laser that shoots a beam of neutrinos.
Put ahead by MIT Professor Joe Formaggio and Dr. Ben Jones from the College of Texas at Arlington, the idea of the neutrino laser was elegant in its ambition.
Cool a cloud of radioactive atoms right down to nanokelvin temperatures — a billionth the coolness of interstellar house — and the atoms ought to settle right into a Bose-Einstein condensate, a weird quantum state the place they act as a single, synchronized entity.
On this state, the physicists proposed, the atoms’ radioactive decay would pace up dramatically, and the neutrinos they emit as a byproduct would stream out collectively in a good, laser-like beam, dramatically shortening radioactive half-lives within the course of.
However in keeping with MTI Professor Wolfgang Ketterle, the Nobel laureate who co-discovered Bose-Einstein condensates in 1995, the thought was too good to be true.
Working with MIT physicists Hanzhen Lin and Yu-Kun Lu, Professor Ketterle presents a two-part evaluation demonstrating that the neutrino laser idea, together with a similar proposal for gamma-rays, is bodily and essentially unimaginable.
Neutrinos are emitted with roughly one million instances extra power than the seen photons utilized in unusual lasers, that means the atom releasing one recoils at velocities equal to Mach 10, quick sufficient that it primarily vanishes from the condensate nearly immediately. This leaves no time for the sort of quantum ‘imprint’ the amplifying impact would require.
“So long as the recoil atom stays within the condensate, it may possibly make the condensate superradiant,” Professor Ketterle mentioned.
“However when a neutrino is emitted at one million electronvolts, the atom recoils at velocities equal to Mach 10, quicker than a fighter jet. That is so quick that the atom would nearly immediately disappear.”
Even in an idealized state of affairs the place an imprint might kind, the researchers found it could perform backward: somewhat than telling the condensate to emit the subsequent neutrino in the identical course, it could sign the alternative, stopping any beam from increase.
They hint this anti-correlation to the truth that neutrinos are fermions — a category of particle, together with electrons, that behaves essentially otherwise from the photons that make unusual superradiant lasers doable.
“These two papers are form of punch one and punch two,” Professor Ketterle mentioned.
“Every paper would have killed the proposal.”
“When a brand new concept — such because the one we proposed — is shared, it’s the responsibility of the neighborhood to scrutinize it,” Professor Formaggio mentioned.
“Such is the scientific course of. Certainly, it was nice to see how our paper generated quite a lot of pondering outdoors of our unique idea. We suspect that can proceed.”
_____
Yu-Kun Lu et al. 2026. Basic Impossibility of a Superradiant Neutrino Laser. Phys. Rev. Lett 137, 101804; doi: 10.1103/8x7k-rwx2
Hanzhen Lin et al. 2026. Can Bose-Einstein Condensates Improve Radioactive Decay? Phys. Rev. Lett 137, 101805; doi: 10.1103/rnx6-wqpf
