Phys.org November 21, 2022
In quantum communications with qubits, the superposition makes it so a quantum pulse cannot be copied. However, with only two levels of superposition, qubits have limited storage space and low tolerance for interference. An international team of researchers (USA – University of Pennsylvania, Duke University, City University of New York, Spain, Italy) has created a chip that outstrips the security and robustness of existing quantum communications hardware. The device’s four-level qudits enable significant advances in quantum cryptography, raising the maximum secrete key rate for information exchange from 1 bit per pulse to 2 bits per pulse. The device offers four levels of superposition and opens the door to further increases in dimension… read more. TECHNICAL ARTICLEÂ
Generation and reconfiguration of SU(4) states. Credit: Nature (2022)Â