Evolution and Applications of Quantum Computing

3Analysis of Design Quantum Multiplexer Using CSWAP and Controlled-R Gates

Virat Tara¹, Navneet Sharma¹*, Pravindra Kumar¹ and Kumar Gautam^2†

¹ Thapar Institute of Engineering and Technology, Quantum Computing Department, Quantum Research and Centre of Excellence, New Delhi, India

² Quantum Computing Department, Quantum Research and Centre of Excellence, New Delhi, India

Abstract

Multiplexing is a technique used widely in electronics and networking to use a common channel or wire to transmit information between circuits or communicating agents on a network. Multiplexing is also economical as it saves the need for multiple transmission channels for different data pins. On the receiver end, a demultiplexer is used to divide the information from the common channel back to multiple data pins. To design a quantum multiplexer, this paper proposes two circuit designs using controlled SWAP (CSWAP) and controlled-R gates. A quantum circuit consists of combinations of quantum gates applied to one or more qubits in order to change or manipulate their quantum state. Here in this paper, we propose circuits for multiplexing multiple qubits. Generalized synthesis is done to construct higher-order multiplexers. Applications based on the proposed circuit design are also discussed along with the limit on the information that can be transferred using a quantum multiplexer which is presented as a corollary to the Holevo’s Theorem. Holevo’s theorem provides an upper limit to the amount of information ...