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Chapter
Quantum Electrodynamics in Superconducting Circuits
We discuss the appearence of quantum electrodynamic effects in superconducting circuits. We concentrate on one simple system; a thick superconducting ring containing a single Josephson weak link. We construct ...
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Article
Quantum theory of the interaction of Josephson junctions with non-classical microwaves
We present a study of the interaction between Josephson junctions in circular superconducting rings and non-classical microwaves, treating both quantum mechanically. A Hamiltonian that describes both inductive...
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Article
The quantum to classical crossover for a weak link capacitor
We consider a model weak link, an ultra-small capacitor subject to tunnelling, to ohmic dissipation and fed with an external displacement current. The framework we employ is the new approach of quantum state d...
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Article
On weak links fed with irreversible currents
We briefly discuss the usual time-reversible descriptions for displacement- and real-current-fed small-capacitance weak links. Many real laboratory current sources deliver charge in an intrinsically irreversib...
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Chapter
The Quantum State Diffusion of an Angular System
State evolution, in contrast to that of a density operator, is particularly relevant for open quantum systems which are individually accessible in experiments. Here we apply state diffusion theory to such a sy...
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Article
Microscopic views of simple macroscopic quantum behaviour
For simple-model microscopic systems, we discuss whether (or not) potentially observable macroscopic quantum behaviour can arise, making explicit two criteria which must be satisfied for this to be possible. W...
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Article
Comments on small capacitors
We discuss the concept of an ultrasmall capacitor and the experimental probing of such objects.
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Chapter and Conference Paper
The Flux Mode and Charge Mode Regimes in Superconducting Weak Link Circuits
In a series of papers [1–4] we have discussed the quantum mechanical description of superconducting weak link circuits in terms of the (integrated) electromagnetic field variables φ, the magnetic flux and Q, t...
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Chapter and Conference Paper
Tunnel Current Modifications due to Finite Tunneling Times
We examine the effects of a finite tunnelling time (independent of its exact definition) on tunnel currents through insulating barriers. In particular we show how the Josephson tunnelling between superconducto...
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Chapter and Conference Paper
Introducing Dissipation in the Schrödinger Picture
We discuss various methods of introducing dissipation to the Schrodinger picture, in the light of the de Broglie-Bohm quantum potential viewpoint. This favours non-linear equations, and Kostin’s Schrödinger-La...
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Chapter and Conference Paper
An Analysis of Non-Linear Behaviour in the Radio Frequency SQUID Magnetometer
Using a model rf-SQUID magnetometer; taken to be a linear classical circuit coupled reactively to a macroscopic quantum circuit, in the adiabatic limit, we investigate the effect of quantum mechanical transiti...
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Chapter
Macroscopic Quantum Objects and their Interaction with External Environments
To gain some appreciation of why any quantum phenomena on the macroscopic scale should be regarded as potentially important to developments in quantum mechanics we have to look back to the origins of the subje...
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Article
Adding dissipation to the Schrödinger equation from the quantum-potential viewpoint
We discuss methods of adding dissipation to the Schrödinger equation in light of the quantum-potential interpretation of quantum mechanics. This favors nonlinear equations in general and Kostin's Schrödinger-L...
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Article
The response of a superconducting weak-link ring to external adiabatic noise
We discuss the response of a superconducting weak-link ring to externally applied adiabatic noise and show that this can be used as a probe of the low-lying energy eigenstates of the ring. We compare the obser...
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Article
Coherent quantum oscillation trajectories
We discuss coherent oscillations in the quantum potential view of quantum mechanics, giving examples for both a superposition of “position” states, and a superposition of “momentum” states.
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Article
Coupled quantum object dynamics
We discuss the dynamical behaviour of coupled quantum objects. This leads to a novel method of observing macroscopic quantum behaviour.
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Article
Weak-link behavior in the small-charge tunneling limit
The coherent behavior of a weak link in the limit where the stored electric energy dominates the charge tunneling energy is discussed. Particular attention is paid to the realization of the source term in the ...
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Article
Electromagnetic duality in quantum circuits
To illustrate the duality between electric and magnetic views of quantum circuits, we compare and contrast the origins of the Josephson frequency and the current bias frequency in each case.
