How does quantum mechanics survive in macroscopic systems in thermal equilibrium with the external environment [1, 2, 3]? Previous experiments show quantum effects at temperatures below a certain crossover temperature [4]–[7], in order to guarantee the condition that the thermal energy be very low with respect to the energy level spacing [3]. We present evidence of macroscopic quantum effects in Josephson junction at temperature well above the crossover temperature. The clear observation of quantum effects up to high temperatures has been obtained by measuring the tunneling rate out of a metastable state while the external energy was changing with time. Thermal mixing of eigenstates does not destroy quantum effects if the rate of change of the external energy is fast with respect to the rate of thermally induced energy transitions between levels. In our experiments this condition has been fulfilled
Macroscopic Quantum Phenomena in Josephson Systems
Silvestrini, P.
2000
Abstract
How does quantum mechanics survive in macroscopic systems in thermal equilibrium with the external environment [1, 2, 3]? Previous experiments show quantum effects at temperatures below a certain crossover temperature [4]–[7], in order to guarantee the condition that the thermal energy be very low with respect to the energy level spacing [3]. We present evidence of macroscopic quantum effects in Josephson junction at temperature well above the crossover temperature. The clear observation of quantum effects up to high temperatures has been obtained by measuring the tunneling rate out of a metastable state while the external energy was changing with time. Thermal mixing of eigenstates does not destroy quantum effects if the rate of change of the external energy is fast with respect to the rate of thermally induced energy transitions between levels. In our experiments this condition has been fulfilledI documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
