For about 15 years, there has been an explosion of interest in the application of concepts derived from quantum information theory to condensed matter systems. One of the main results of this activity is t”he discovery of the “entanglement transition”, a phenomenon whose importance had not been recognised through more conventional field-theory approaches. In a recent preprint [1] we identify theoretically some of its experimental consequences. Specifically, we show that the entanglement transition has particularly important consequences for clustered materials – i.e. those made up of separate, finite-size units which are approximately independent of each other.
Our work [1] shows that the entanglement transition is more distinct from better-understood phenomena, such as quantum critical points, than had hitherto been
noticed. It is remarkable, for example, that the predicted neutron scattering cross-section has sharp manifestations of the entanglement transition in systems so small that any signature of a quantum critical point has been washed out by finite-size fluctuations.
There are many different realisations of finite-size quantum materials. These include molecular magnets which are themselves extremely topical within the physics and chemistry communities, but also many other nano-engineered and trapped ion/atom systems. Most of the work on molecular magnets has focused on quantities such as their net moment rather than the internal degrees of freedom which are summed to produce the net moment. Our work suggests examining, via neutron scattering, the correlations between these internal degrees of freedom to observe entanglement transitions. For trapped ions/atoms, optical methods should yield similar information, and for artificial clusters of atoms arranged on surfaces via scan probe tips, spin-polarized scanning tunneling microscopy should produce the corresponding images. Our results will thus be of interest to a broad range of communities working with cold atoms and mesoscopic condensed matter systems generated by both top-down (e.g. via electron beam writing or scan probe manipulation) and bottom-up (e.g. via chemical synthesis) methods.
This preprint [1] is the result of Hannah Irons’ PhD work in collaboration with Toby Perring, Luigi Amico and Gabriel Aeppli.
References:
[1] Hannah R. Irons, Jorge Quintanilla, Toby G. Perring, Luigi Amico, Gabriel Aeppli, “Experimental implications of the entanglement transition in clustered quantum materials”, arXiv:1704.08146 [cond-mat.str-el].