Questions tagged [josephson-junction]

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Characteristic lengths in SNS Josephson Junction

An S-N-S Josephson junction is formed by two Superconducting (S) leads separated by a normal metal (N) which acts like the weak link. While studying, I often encounter the words diffusive, long, ...
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Origin of Josephson voltage equation?

i cant find a satisfying explanation, and I cant figure it out myself, a derivation for the josephson equation: $$U(t)=\frac{\hbar}{2e}\frac{d\phi}{dt}$$ where $U(t)$ is the voltage, and $\phi$ is the ...
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Josephson junction characteristics

Is there a physical interpretation for the characteristic frequency and voltage of a josephson junction? $$ \omega_c = \frac{2 \pi I_0 R}{\Phi_0} $$ $$ V_c = I_0 R $$ $I_0$ is the critical current ...
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Determining the position and spectral weight of Andreev states from a retarded Green Function

I'm trying to understand a result from the paper Josephson current through a correlated quantum level: Andreev states and $\pi$ junction behavior by Vecino, Martin-Rodero and Yetati (2003). ArXiv link ...
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How the critical current of Josephson junction is related to the junction thickness and other fundamental constants?

In Josephson effect a quantum (critical) current is found to pass across the junction without an applied voltage. How one can relate this current to the fundamental constants and the junction ...
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Treating $-E_J \vert{\cos{(\hat{\theta}/2)}}\vert$ in the charge basis

I'm trying to write down the Hamiltonian for a Cooper pair box in the charge basis in the scenario where the Josephson potential term is not $-E_J \cos{\hat{\theta}}$, but $-E_J \vert{\cos{(\hat{\...
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Is the hierarchy of Andreev bound state transmission probabilities fixed?

My question is regarding Andreev bound states and their transmission probabilities. But to make this self-contained, lets quickly recap, for which I will draw from Tosi, L., Metzger, C., Goffman, M. F....
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Vanishing of Coulomb blockade/charge dispersion in high transparency Josephson junctions

I was recently reading the paper Coulomb Blockade in Superconducting Quantum Point Contacts by Averin from 1999 (see here for the ArXiV, here for the PRL). In here he discusses a peculiar phenomenon:...
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Josephson energy versus magnetic field in S-Nanowire-S junctions

I was reading the proposal Microwave transitions as a signature of coherent parity mixing effects in the Majorana-transmon qubit by Ginossar and Grosfeld (2014) in which they envision a superconductor-...
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181 views

Original derivation of the Josephson effect

In my efforts to understand Josephson's original derivation of the effect that bears his name, I was led to Eqs. 3.68 on pg. 69 from Tinkham's book (Introduction to Superconductivity, McGraw-Hill, 2nd ...
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252 views

Josephson junction exceeding the coherence length of the cooper pair

In this recent paper http://arxiv.org/abs/1504.03286, the authors present the data that they measured Fraunhofer-like diffraction pattern in a Josephson junction with graphene sandwiched between ...
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Definition of Josephson current

Consider a system of two superconductors (with Hamiltonian $H_{SC1}$ and $H_{SC2}$) weakly tunnel coupled via some intermediate system, i.e. an insulator, a ferromagnet, a quantum dot, etc. (described ...
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The Hamiltonian for Josephson Junctions

In the Feynman Lectures on physics, Feynman says the amplitudes across a Josephson Junction should be related by the following, where the subscript denotes the side of the junction that the amplitude ...
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321 views

What is the difference between a Josephson junction and a superconducting tunnel junction?

I am wondering if there is any difference between a Josephson junctions and superconducting tunnel junctions. I appreciate a good explanation.
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What does the $I$-$V$ curve in josephson junction mean?

According to the $I$-$V$ curve for Josephson junction tunneling for S-I-S (superconductor-insulator-superconductor), Do we have any tunneling current for $0< V\leq V_c$? If yes, then why don't we ...
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759 views

What is the temperature dependence of the critical current in weak links?

I am now working on hybrid Josephson junctions that are supposed to be tunnel junctions, so that the temperature dependence of the critical current should be $$ I_c (T)=\frac{\pi}{2}\frac{\Delta(T)}{...
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773 views

Analogies between Fraunhofer diffraction and Josephson junctions

There are several analogies between diffraction patterns and Josephson junctions, especially between a double slit experiment and two Josephson junctions in a superconducting ring (like this): Both ...
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68 views

Why are the Fermi levels of two different superconductors in a Josephson junction the same?

ELECTRON TUNNELING AND SUPERCONDUCTIVITY (Fig. 10A)– This is Giaever's Nobel lecture about how to measure the energy gap of each superconductor using a Josephson junction. I wonder why we can assume ...
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What can I expect to see in a oscillator exhibiting bifurcation?

I have a program which aims to simulate a Josephson Bifurcation Amplifier. I am currently trying to obtain a plot of the probability of bifurcation as a function of the ratio between the driving and ...