Superconducting charge qubits from a microscopic many-body perspective
arXiv:0709.3460 · doi:10.1088/0953-8984/19/43/436211
Abstract
The quantised Josephson junction equation that underpins the behaviour of charge qubits and other tunnel devices is usually derived through cannonical quantisation of the classical macroscopic Josephson relations. However, this approach may neglect effects due to the fact that the charge qubit consists of a superconducting island of finite size connected to a large superconductor. We show that the well known quantised Josephson equation can be derived directly and simply from a microscopic many-body Hamiltonian. By choosing the appropriate strong coupling limit we produce a highly simplified Hamiltonian that nevertheless allows us to go beyond the mean field limit and predict further finite-size terms in addition to the basic equation.
Accepted for J Phys Condensed Matter
References in corpus (14)
- Quantum state engineering with Josephson-junction devices
- Coherent control of macroscopic quantum states in a single-Cooper-pair box
- Manipulating the Quantum State of an Electrical Circuit
- Superconducting Circuits and Quantum Information
- Quantum oscillations in two coupled charge qubits
- Josephson-Junction Qubits with Controlled Couplings
- Quantum Manipulations of Small Josephson Junctions
- Exactly solvable Richardson-Gaudin models for many-body quantum systems
- Coherent dynamics of a Josephson charge qubit
- Enhanced Macroscopic Quantum Tunneling in BiSrCaCuO Intrinsic Josephson Junction Stacks
- Single-shot measurement of the Josephson charge qubit
- Strong Coupling Expansion for the Pairing Hamiltonian
- Review: Superconductivity in ultrasmall metallic grains
- Arrays of Cooper Pair Boxes Coupled to a Superconducting Reservoir: `Superradiance' and `Revival.'