Physicists at the University of California, Los Angeles, have developed a technique for directly mapping the energy levels of coupled silicon quantum dots, offering a clearer picture of the microscopic structures used in experimental quantum processors.
Quantum dots can confine individual electrons, whose spin and other quantum properties may encode information. But understanding how their internal energy levels change under different operating conditions has proved difficult.
The researchers examined a pair of quantum dots while varying the energy difference between them, their coupling strength and an applied magnetic field.
They observed how isolated dots develop molecule-like bonding and antibonding energy states as their coupling increases. Their measurements also revealed magnetic-field-dependent energy splitting and differences between electron spin configurations.
The findings complement research into silicon-based quantum processors and efforts to identify fluctuations that undermine quantum-bit reliability.
By exposing energy structures that are otherwise difficult to measure, the technique could help scientists characterize future quantum devices.
The study demonstrates a measurement capability, not a functioning large-scale quantum computer.