Transfer of arbitrary quantum states from one input cavity to multiple output cavities via a superconducting-qudit switch

Abstract

Quantum state transfer, from one location to multiple different locations via the control of a quantum switch, is of fundamental interest in quantum physics. It has potential applications in networked quantum communication, information processing, and development of quantum technologies and quantum functional devices. Here we consider a circuit-QED system, which consists of an input microwave cavity, n output microwave cavities, and an (n+2)-level superconducting (SC) qudit (acting as a multiplex switch). We show that arbitrary quantum states initially stored in the input cavity can be transferred to n different output cavities when the SC-qudit switch is in different states. The operational time does not depend on the output-cavity number. Since the two auxiliary higher-energy levels of the qudit are almost not excited during the state transfer, decoherence from these two levels is greatly suppressed. The state transfer can be realized deterministically because no state measurement is needed. We further numerically analyze the experimental feasibility of transferring arbitrary states of a photonic qubit from one input cavity to two output cavities via the control of a SC-flux-ququart switch (a four-level system). This proposal may be extended to accomplish the same task in other physical systems, where the switch is a multilevel artificial atom of different types and each cavity is a microwave or optical cavity.

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