Wednesday, September 29, 2021

One of nature’s key constants is much larger in a quantum material

Are we witnessing the emergence of a new physics? Is the next Albert Einstein ready?

Perhaps these findings indicate that one nature's key constants, i.e. fine structure constant, is an artifact, but not really a fundamental physical constant.

"... If the fine-structure constant throughout the cosmos were as large as the one in quantum spin ices, “the periodic table would only have 10 elements,” ...
Quantum spin ices are a class of substances in which particles can’t agree. The materials are made up of particles with spin, a quantum version of angular momentum, which makes them magnetic. In a normal material, particles would come to a consensus below a certain temperature, with the magnetic poles lining up in either the same direction or in alternating directions. But in quantum spin ices, the particles are arranged in such a way that the magnetic poles, or equivalently the spins, can’t agree even at a temperature of absolute zero ...
The impasse occurs because of the materials’ geometry: The particles are located at the corners of an array of pyramids that are connected at the corners. ..."

From the abstract:
''Condensed-matter systems provide alternative “vacua” exhibiting emergent low-energy properties drastically different from those of the standard model. A case in point is the emergent quantum electrodynamics (QED) in the fractionalized topological magnet known as quantum spin ice, whose magnetic monopoles set it apart from the familiar QED of the world we live in. Here, we show that the two greatly differ in their fine structure constant α, which parametrizes how strongly matter couples to light: α QSI is more than an order of magnitude greater than 
α QED≈1/137. Furthermore, α QSI, the emergent speed of light, and all other parameters of the emergent QED, are tunable by engineering the microscopic Hamiltonian. We find that αQSI can be tuned all the way from zero up to what is believed to be the strongest possible coupling beyond which QED confines. In view of the small size of its constrained Hilbert space, this marks out quantum spin ice as an ideal platform for studying exotic quantum field theories and a target for quantum simulation. ...
to calculate the fine-structure constant in quantum spin ices for the first time. The team pegged the number at about 1/10, instead of 1/137. What’s more, the researchers found that they could change the value of the fine-structure constant by tweaking the properties of the theoretical material. ..."

One of nature’s key constants is much larger in a quantum material | Science News The fine-structure constant is 10 times its normal value in the material, giving a peek at an alternate universe




No comments: