Converting qubits

Dressed qubits.

Inherent gate errors can arise in quantum computation when the actual system Hamiltonian or Hilbert space deviates from the desired one. Two important examples we address are spin-coupled quantum dots in the presence of spin-orbit perturbations to the Heisenberg exchange interaction, and off-resonant transitions of a qubit embedded in a multilevel Hilbert space. We propose a "dressed qubit" tra...

Flying Qubits

'This would for example allow transferring information from superconducting quantum bits to the "flying qubits" in the visible light range and back', envision the creators of the theory for the device, Tero Heikkilä, Professor at the University of Jyväskylä, and Academy Research Fellow Francesco Massel. Therefore, the method has potential for data encryption based on quantum mechanics, i.e. qua...

Overlapping Qubits

An ideal system of n qubits has 2 dimensions. This exponential grants power, but also hinders characterizing the system’s state and dynamics. We study a new problem: the qubits in a physical system might not be independent. They can “overlap,” in the sense that an operation on one qubit slightly affects the others. We show that allowing for slight overlaps, n qubits can fit in just polynomially...

Producing cluster states in charge qubits and flux qubits.

We propose a method to efficiently generate cluster states in charge qubits, both semiconducting and superconducting, as well as flux qubits. We show that highly entangled cluster states can be realized by a "one-touch" entanglement operation by tuning gate bias voltages for charge qubits. We also investigate the robustness of these cluster states for nonuniform qubits, which are unavoidable in...

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