In this part 6, we will be discussing about "Superconductor technology", "Superconducting qubits" and "Josephson Junction".

Superconductor Technology:-
Superconductor was discovered by a Dutch physicist named Heike Kamerlingh Onnes (1911), which is termed as a quantum mechanical process that conducts electricity without resistance. This phenomenon is characterized by the "Meissner effect".
Meissner effect states the expulsion of a magnetic field from a superconductor during its transition to the superconducting state. This effect was discovered by the German physicists:- Walther Meissner and Robert Ochsenfeld in 1933.
The Superconductor technology can be applied for various applications such as quantum (DELTT) transistors, molecule scale processors, DNA based processors, SQUIDS, development of superconducting degaussing scale and Lenslet optical DSP.
The emerging ones uses "flux pinning" which it leads to the development of superconducting light detectors and superconducting x-ray detectors.

As per in quantum computing, there comes "Superconducting quantum computing".
The superconducting quantum computing is termed as involving nano-fabricated superconducting electrodes that is coupled by means of Josephson junction.
Under superconducting quantum computing, there comes "Superconducting qubits". In the superconducting electrode: the phase and the charge are conjugate variables.

Superconducting qubits:-
The superconducting qubits consists of three families namely,
1. Charge qubits
Charge qubits are termed as a natural way in using the position of a single access electron in a double dot system. They are made from the cooper pair box (tiny superconducting thingy) which is coupled by Josephson Junction.
2. Flux qubits (or persistent current qubits)
Flux qubits are termed as the loops of superconducting metal interrupted by the number of Josephson junctions. The qubit states are defined by circulating the current, which can flow either clockwise or counter-clockwise.
3. Phase qubits
The phase qubit is a superconducting device based upon the Superconductor-Insulator-Superconductor (SIS) of Josephson Junction, which are designed inorder to work as a quantum bit or qubit.
The phase bit is a current-biased Josephson junction, which works under zero voltage state in non-zero current bias.

Josephson Junction:-
The Josephson junction is termed as formation of a thin layer in a non-superconducting material between the two layers of a superconducting material. The two layers of a superconducting material are two superconducting electrodes, which is called as Josephson phase.
If the barrier appears to be an insulator, then it has to be in the order of 30 angstroms thick or less.
This junction thingy was predicted by Brian Josephson in 1962.
Josephson Junction (JJ) is defined as,
Is = Ic sin(φ)

Where,
Φ = phase difference of the superconducting wave
functions of two electrodes
Ic = Critical current
Is = Super current

If you are more interested to learn Josephson Junction, then click here to download the sample PDF from Pearson Higher Education.

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