Paper by Immanuel Bloch published in journal Nature

Any matter occurs in differ­ent phases, which can merge into one another. An example of this is water, which exists in liquid form, as ice or steam — depend­ing on the exter­nal condi­tions. The differ­ent physi­cal phases have the same chemi­cal compo­si­tion, but a differ­ent degree of inter­nal order. If the temper­a­ture or pressure changes, for example, the water changes into a differ­ent phase at a certain point. However: In some materi­als, there are phases between which a transi­tion is not possi­ble because they are protected by a certain form of symme­try. Physi­cists refer to these as topolog­i­cal phases.

One example of this is the Haldane phase, named after the 2016 Nobel Prize winner in physics Duncan Haldane, which occurs in antifer­ro­mag­netic spin‑1 chains. The team of Immanuel Bloch and Timon Hilker at MPQ has now succeeded in realiz­ing this exotic state of matter in a simple system of ultra­cold atoms. Using a quantum gas micro­scope, they brought the atomic spins into the desired shape, measured the proper­ties of the system and thus found the hidden inter­nal order typical of the Haldane phase.

With their results, the Max Planck researchers have not only laid the founda­tion for exper­i­men­tally verify­ing theoret­i­cal predic­tions about topolog­i­cal phases. Their new findings could also find practi­cal appli­ca­tion in the future – in quantum comput­ers. With the help of topolog­i­cal phases, it would be possi­ble to ensure the stabil­ity of qubits, the funda­men­tal comput­ing units of quantum computers.

Congrat­u­la­tions Immanuel Bloch!