The results could lead to incredible advancements in quantum technology.
Quantum entanglement, one of the strangest and most elusive phenomena in quantum mechanics, is not fully understood by scientists.
The phenomenon is accepted as fact nowadays, but a century ago, quantum entanglement was the center of theoretical debate — it even baffled Albert Einstein. Entanglement states that two particles can be inextricably linked, no matter the distance between them, and this connection results in the state of one particle instantly influencing the state of the other.
That doesn’t even sound possible, but it is real and has been observed. Creating the phenomena at the macroscopic scale is very difficult since entanglement requires that particles must start in a highly ordered state. However, this is not conducive in thermodynamics, the process that governs the interaction between heat and other forms of energy.
“The macroscopic world that we are used to seems very tidy, but it is completely disordered at the atomic scale. The laws of thermodynamics generally prevent us from observing quantum phenomena in macroscopic objects,” said Paul Klimov, a graduate student in the Institute for Molecular Engineering and lead author of the study.
Scientists have to overcome the thermodynamic barrier in order to achieve entanglement at macroscopic scales by cooling temperatures to near absolute zero (-454 degrees Fahrenheit) and applying huge magnetic fields. Or rather, they used to.
Researchers from UChicago and Argonne National Laboratory were able to create entanglement at room temperature by using infrared laser light to align the magnetic states of electrons and nuclei. Then, they used electromagnetic pulses to entangle them. This caused pairs of electrons and nuclei of the semiconductor SiC, in an approximate volume of a red blood cell, to become entangled. Although that sounds very small, thousands of particles can be linked in the volume of a red blood cell.
“We know that the spin states of atomic nuclei associated with semiconductor defects have excellent quantum properties at room temperature,” said Awschalom, the Liew Family Professor in Molecular Engineering and a senior scientist at Argonne. “They are coherent, long-lived and controllable with photonics and electronics. Given these quantum ‘pieces,’ creating entangled quantum states seemed like an attainable goal.”
The results spur hope for future quantum devices and technological advances.
In the short term, given that the semiconductor SiC is biofriendly, biological sensing inside a living organism could be used to pick up extremely small changes in particle levels.
In the long term, it may be possible to go from entangled states on the same SiC to entangled states across SiC chips. That technology could be used for synchronizing global positioning system satellites, or communicating information secured from eavesdroppers by the laws of physics.