Environment-Protected Solid State Based Distributed Charge Qubit

Abstract

A novel solid state based charge qubit is presented. The system consists of a one-dimensional wire with a pair of qubits embedded at its center. It is shown that the system supports collective states localized in the left and right sides of the wire and therefore, as a whole, performs as a single qubit. The couplings between the ground and excited states of the two central qubits are inversely proportional making them fully asynchronized and allowing for coherent manipulation and gate operations. Initialization and measurement devices, such as leads and charge detectors, connected to the edges of the wire are modeled by a continuum of energy states. The coupling to the continuum is discussed using the effective non-Hermitian Hamiltonian. At weak continuum coupling, all internal states uniformly acquire small decay widths. This changes dramatically as the coupling strength increases: the width distribution undergoes a sharp restructuring and is no longer uniformly divided among the eigenstates. Two broad resonances localized at the ends of the wire are formed. These superradiant states (analogous to Dicke states in quantum optics), effectively protect the remaining internal states from decaying into the continuum and hence increase the lifetime of the qubit. Environmental noise is introduced by considering random Gaussian fluctuations of electronic energies. The interplay between decoherence and superradiance is studied by solving the stochastic Liouville equation. In addition to increasing the lifetime, the emergence of the superradiant states increases the qubit coherence.

12 pages, 13 figures

References in corpus (22)

• Review article: Linear optical quantum computing
• Optical Quantum Computing
• Quantum computing with trapped ions
• Coherent manipulation of electronic states in a double quantum dot
• Quantum Coherence in a One-Electron Semiconductor Charge Qubit
• Computing prime factors with a Josephson phase qubit quantum processor
• Differential Charge Sensing and Charge Delocalization in a Tunable Double Quantum Dot
• Superconducting quantum node for entanglement and storage of microwave radiation
• Electrical control of a solid-state flying qubit
• Qubits with electrons on liquid helium
• Super-Radiant Dynamics, Doorways, and Resonances in Nuclei and Other Open Mesoscopic Systems
• Superradiance Transition in Transport Through Nanosystems
• Charge sensing and controllable tunnel coupling in a Si/SiGe double quantum dot
• Superradiance Transition in Photosynthetic Light-Harvesting Complexes
• A Stochastic Liouville Equation Approach for the Effect of Noise in Quantum Computations
• Non-Hermitian Hamiltonian approach to the microwave transmission through one- dimensional qubit chain
• Cooperative robustness to dephasing: single-exciton Superradiance in a nanoscale ring to model natural light-harvesting systems
• Coherent transport in multi-branch circuits
• Transport through side-coupled double quantum dots: from weak to strong interdot coupling
• Coupling a single Nitrogen-Vacancy center to a superconducting flux qubit in the far off resonance regime
• Tunable capacitive inter-dot coupling in a bilayer graphene double quantum dot
• Quantum signal transmission through a single-qubit chain

Cited by in corpus (2)

• A generalization of Bloch's theorem for arbitrary boundary conditions: Theory
• Robustness of Dicke subradiance against thermal decoherence