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Борис В. Васильев Сверхтекучесть и Сверхпроводимость

Борис В. Васильев
Сверхтекучесть и Сверхпроводимость

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êîëüöà, íèãäå íå ïîäõîäÿ áëèçêî ê ïîâåðõíîñòè:<br />

(39) <br />

òî ïîëó÷èòñÿ<br />

(40)<br />

∮<br />

∮<br />

∇θds = 2e<br />

c<br />

∮<br />

∇θds = 2e<br />

c Φ,<br />

Ads,<br />

òàê êàê ïî îïðåäåëåíèþ ìàãíèòíîãî ïîòîêà ÷åðåç<br />

ëþáóþ ïåòëþ<br />

(41) Φ =<br />

∮<br />

Ads.<br />

Êîíòóðíûé èíòåãðàë ∮ ∇θds äîëæåí áûòü êðàòåí<br />

2π, ÷òîáû îáåñïå÷èòü îäíîçíà÷íîñòü ïàðàìåòðà<br />

ïîðÿäêà ïðè îáõîäå ïî êîíòóðó. Òàêèì îáðàçîì<br />

ìàãíèòíûé ïîòîê, çàõâà÷åííûé ñâåðõïðîâîäÿùèì<br />

êîëüöîì äîëæåí áûòü êðàòåí êâàíòó<br />

ìàãíèòíîãî ïîòîêà:<br />

(42) Φ 0 = 2πc<br />

2e ,<br />

÷òî òî÷íî ïîäòâåðæäàåòñÿ ñîîòâåòñòâóþùèìè<br />

èçìåðåíèÿìè.<br />

Ýòî î÷åíü âàæíûé ðåçóëüòàò äëÿ ïîíèìàíèÿ<br />

ôèçèêè ñâåðõïðîâîäèìîñòè.<br />

Òàêèì îáðàçîì, òåîðåòè÷åñêèå ïðåäñêàçàíèÿ,<br />

ïîäòâåðæäàþùèåñÿ èçìåðåíèÿìè, ãîâîðÿò, ÷òî<br />

ñâåðõïðîâîäèìîñòü îñóùåñòâëÿåòñÿ áëàãîäàðÿ<br />

òîìó, ÷òî åå íîñèòåëè èìåþò çàðÿä 2e, ò.å. ïðåäñòàâëÿþò<br />

ñîáîé äâà ñïàðåííûõ ýëåêòðîíà.<br />

54

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