• Research

Researchers at the University of Illinois at Urbana-Champaign have constructed a quantum-mechanical state in which the colors of three photons are entangled with each other. The state is a special combination, called a W state, that retains some entanglement even if one of the three photons is lost, which makes it useful for quantum communication. Such entangled states also enable novel quantum applications and tests of fundamental physics. 

The uniqueness of this work is that the researchers used color, or the energy of the photons, as the entangling degree of freedom, while previous work used polarization. The energy of a photon cannot be easily changed, which reduces the possibility of errors when the energy-entangled W state is propagating over a long distance. The state was verified for the first time by measuring information about the two-photon sub-systems. Their findings are published in Physical Review Letters.
  • Research
  • Atomic, Molecular, and Optical Physics

Physicists at the University of Illinois at Urbana-Champaign have observed a magnetic phenomenon called the “anomalous spin-orbit torque” (ASOT) for the first time. Professor Virginia Lorenz and graduate student Wenrui Wang, now graduated and employed as an industry scientist, made this observation, demonstrating that there exists competition between what is known as spin-orbit coupling and the alignment of an electron spin to the magnetization. This can be thought of as analogous to the anomalous Hall effect (AHE).