Researchers at the California Institute of Technology (Caltech) and a team from the University of Vienna have collaborated to cool a miniature mechanical object to its lowest possible energy state using laser light — paving the way for the development of exquisitely sensitive detectors as well as for quantum experiments that scientists have long dreamed of conducting.
The researchers engineered a nanoscale object — a tiny mechanical silicon beam — such that laser light of a carefully selected frequency can enter the system, and, once reflected, can carry thermal energy away, cooling the system.
By carefully designing each element of the beam as well as a patterned silicon shield that isolates it from the environment, the researchers were able to use the laser cooling technique to bring the system down to the quantum ground state, where mechanical vibrations are at an absolute minimum. Such a cold mechanical object could help detect very small forces or masses, whose presence would normally be masked by the noisy thermal vibrations of the sensor.
This advance could open doors to allow researchers to conduct interesting quantum-mechanical experiments, such as showing that a mechanical system could be coaxed into a quantum superposition — a bizarre quantum state in which a physical system can exist in more than one position at once.
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