Quantum superposition of three macroscopic states and superconducting qutrit detector

Abstract

Superconducting quantum coherent circuits have opened up a novel area of fundamental low-temperature science since they could potentially be the element base for future quantum computers. Here we report a quasi-three-level coherent system, the so-called superconducting qutrit, which has some advantages over a two-level information cell (qubit), and is based on the qutrit readout circuit intended to measure individually the states of each qubit in a quantum computer. The designed and implemented radio-frequency superconducting qutrit detector (rf SQUTRID) with atomic-size ScS-type contact utilizes the coherent-state superposition in the three-well potential with energy splitting Delta E_01/k_B=1.5 K at the 30th quantized energy level with good isolation from the electromagnetic environment. The reason why large values of Delta E_01 (and thus using atomic-size Nb-Nb contact) are required is to ensure an adiabatic limit for the quantum dynamics of magnetic flux in the rf SQUTRID.

9 pages, 5 figures, in v.3: text extended, inset in figure 1 (the device design) added

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Cited by in corpus (7)

• Single-step implementation of a multiple-target-qubit controlled phase gate without need of classical pulses
• How to build Hamiltonians that transport noncommuting charges in quantum thermodynamics
• Periodically Driven Three-Level Systems
• Realisation of Qudits in Coupled Potential Wells
• Stochastic resonance in an RF SQUID with shunted ScS junction
• A tunable coupler with ScS quantum point contact to mediate strong interaction between flux qubits
• Experimental observation of induced stochastic transitions in multi-well potential of RF SQUID loop