Superfluid
Superfluidity is a state of matter characterised by the complete absence of viscosity. Thus superfluids, placed in a closed loop, can flow endlessly without friction.The superfluid transition is displayed by quantum liquids[?] below a characteristic transition temperature. The most abundant isotope of Helium, 4He, becomes superfluid at temperatures below 2.17K (-270.98°C). The less abundant isotope, 3He, becomes superfluid at a much lower temperature: 2.6mK (only a few thousands of a degree above the absolute zero, that is -273.15°C).
Although the phenomenology of superfluidity in these two systems is very similar, the nature of the two superfluid transitions is very different. 4He atoms are bosons, and their superfluidity can be understood in terms of the Bose statistics[?] that they obey. Specifically, the superfluidity of 4He can be regarded as the generalisation of Bose-Einstein condensation (which takes place only in a non-interacting gas) to interacting systems. On the other hand, 3He atoms are fermions, and the superfluid transition in this system is described by a generalisation of the BCS theory of superconductivity. In it, Cooper pairing[?] takes place between atoms rather than electrons, and the attractive interaction between them is mediated by spin fluctuations rather than phonons. A unified description of superconductivity and superfluidity is possible in terms of Gauge symmetry breaking[?].
One important application of superfluidity is in dilution refrigerators[?].
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closed and the awful tragedy, then reopening--that every spark of
The general onslaught of the League with Ferdinand, Maximilian of
irresolute, and wavering line of Protestantism across the whole of Europe
heretic, was the war-cry of the Emperor. The King of Spain, as we have
at Brussels, was nursing sanguine hopes and weaving elaborate schemes for
send an army of Jesuits thither to break the way to the reconquest.
Papists, would have been in Barneveld's opinion like giving up Julich and
between Catholicism and Protestantism was breaking out. There had been
which had closed. It was not desirable to give a chance for their
reference to the 13th Article of the Union. Words could not more plainly
affairs of any one of the Provinces than had been done by that celebrated
insertion of a pledge to maintain the Evangelical, Reformed, religion
evident a truth, that a confederacy which had admitted and constantly
noninterference with their religious affairs, had no right to lay down
oath of stadholder and magistrates in Holland to maintain the Reformed
begun, and it was mere arrogant assumption on the part of the Contra-
Remonstrants from its folds.
He had steadily done his utmost to assuage those dissensions while
provincial synod to be amicably assisted by divines from neighbouring
the Seven Provinces, because it would have been an open violation of the
of conscience. He admitted that he had himself drawn up a protest on the
decree for the National Synod as a breach of the Union, declaring it to
protest as oldest member present, while Grotius as the youngest had acted
.
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