Bi$_2$Sr$_2$CaCu$_2$O$_{8+\delta}$ intrinsic SQUIDs as candidates of high-T$_c$ phase qubits
ORAL
Abstract
An intrinsic SQUID is a superconducting ring made of Bi$_2$Sr$_2$CaCu$_2$O$_{8+\delta}$ single crystal, intercepted by two intrinsic Josephson junction stacks. The inductance parameter $\beta_L$ can be tuned in a wide range by changing the height and the cross-section area of the stacks. When biased with dc current, the device showed typical properties of hysteretic dc-SQUIDs. When a device was coupled with a coil and a Nb readout dc-SQUID, typical rf-SQUID behavior was observed. By choosing a proper reset field, quantum escape from a single minimum has been measured on a sample of $\beta_L\sim10$. The escape rate can be fine-tuned by applying short pulses down to 1 ns, which allows a fast readout technique. With these prerequisites achieved, our experiments have opened the path to directly using these intrinsic SQUIDs as high-T$_c$ phase qubits. The first attempts to measure Rabi oscillations on these devices will be discussed.
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