In physics, the Josephson effect is a phenomenon that occurs when two superconductors are placed in proximity, with some barrier or restriction between them.
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18 Facts About Josephson effect
2.
The Josephson effect has many practical applications because it exhibits a precise relationship between different physics quantities, such as voltage and frequency, facilitating highly accurate measurements.
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3.
Josephson effect produces a current, known as a supercurrent, that flows continuously without any voltage applied, across a device known as a Josephson junction .
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4.
Josephson effect junctions have important applications in quantum-mechanical circuits, such as SQUIDs, superconducting qubits, and RSFQ digital electronics.
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5.
Josephson effect is named after the British physicist Brian David Josephson, who predicted in 1962 the mathematical relationships for the current and voltage across the weak link.
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6.
The DC Josephson effect had been seen in experiments prior to 1962, but had been attributed to "super-shorts" or breaches in the insulating barrier leading to the direct conduction of electrons between the superconductors.
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7.
Josephson effect was the first to predict the tunneling of superconducting Cooper pairs.
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8.
The Josephson effect junction count of a device is used as a benchmark for its complexity.
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9.
The Josephson effect has found wide usage, for example in the following areas.
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10.
In precision metrology, the Josephson effect provides an exactly reproducible conversion between frequency and voltage.
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11.
Since the frequency is already defined precisely and practically by the caesium standard, the Josephson effect is used, for most practical purposes, to give the standard representation of a volt, the Josephson voltage standard.
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12.
Josephson effect is used for the most precise measurements of elementary charge in terms of the Josephson constant and von Klitzing constant which is related to the quantum Hall effect.
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13.
Josephson effect junctions are integral in superconducting quantum computing as qubits such as in a flux qubit or others schemes where the phase and charge act as the conjugate variables.
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14.
Josephson effect has been observed in superfluid helium quantum interference devices, the superfluid helium analog of a dc-SQUID.
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15.
Josephson effect can be calculated using the laws of quantum mechanics.
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16.
The critical current of the Josephson effect junction depends on the properties of the superconductors, and can be affected by environmental factors like temperature and externally applied magnetic field.
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17.
DC Josephson effect is a direct current crossing the insulator in the absence of any external electromagnetic field, owing to tunneling.
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18.
Therefore the energy stored in a Josephson effect junction is a state function, which can be defined as:.
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