A transmon based quantum switch for a quantum random access memory

In this thesis, the necessary elements to build up a quantum switch, the central element in a quantum random access memory, are proposed and analyzed. A network with quantum switches at its nodes forms the bifurcation path that leads an address register from a root node to an array of memory cells, activating, quantum coherently, only the quantum switches that the register encounters in its path to the memory cells. Transmon qubits and SQUIDs are used to design a superconducting device capable of routing a register of microwave photons through a bifurcation network, allowing for superposition of paths. In order to give rise to all the required interactions between the device and the address register, a non-linear capacitor, composed of two plates with carbon nanotubes in between, is introduced into the transmon. The dynamic operation of the quantum switch is analyzed using Langevin equations and a scattering approach, and probabilities of reflection and transmission of photons by ...Show moreIn this thesis, the necessary elements to build up a quantum switch, the central element in a quantum random access memory, are proposed and analyzed. A network with quantum switches at its nodes forms the bifurcation path that leads an address register from a root node to an array of memory cells, activating, quantum coherently, only the quantum switches that the register encounters in its path to the memory cells. Transmon qubits and SQUIDs are used to design a superconducting device capable of routing a register of microwave photons through a bifurcation network, allowing for superposition of paths. In order to give rise to all the required interactions between the device and the address register, a non-linear capacitor, composed of two plates with carbon nanotubes in between, is introduced into the transmon. The dynamic operation of the quantum switch is analyzed using Langevin equations and a scattering approach, and probabilities of reflection and transmission of photons by (or through) the switch are computed, both for single- and two-photon processes. Computations show that, with parameters taken from up-to-date similar devices, probabilities of success are above 94%. Applications of quantum random access memories are discussed, as well as other applications of quantum switches. Also, solutions are proposed to the challenges that emerge during the study of the dynamics of the quantum switch.Show less

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A transmon based quantum switch for a quantum random access memory