{"product_id":"quantix-flux-quantum","title":"Quantix – Magnetic Flux Quantum \/ Φ0 = h\/2e Physics Sticker","description":"\u003cp\u003eQuantix, an ice monk of The SI Guard, steps across a frozen superconducting lake of vortex stones, each holding one quantum of flux.\u003c\/p\u003e\u003ch3\u003eThe Physics\u003c\/h3\u003e\u003cp\u003eIn a superconducting ring the electrons pair up into Cooper pairs and share a single macroscopic wavefunction. The phase must come back to itself around the loop, so the fluxoid (the flux, plus a small supercurrent term) is quantised in whole multiples of Φ\u003csub\u003e0\u003c\/sub\u003e. In a type-II superconductor the field enters as Abrikosov vortices, each carrying one Φ\u003csub\u003e0\u003c\/sub\u003e, arranged in a triangular lattice.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eΦ\u003csub\u003e0\u003c\/sub\u003e = h\/2e ≈ 2.067 833 848 × 10⁻¹⁵ Wb\u003c\/strong\u003e\u003c\/p\u003e\u003cul\u003e\n\u003cli\u003eΦ\u003csub\u003e0\u003c\/sub\u003e: magnetic flux quantum (Wb)\u003c\/li\u003e\n\u003cli\u003eh: Planck constant (exact)\u003c\/li\u003e\n\u003cli\u003e2e: charge of a Cooper pair\u003c\/li\u003e\n\u003c\/ul\u003e\u003cp\u003eSince the 2019 SI fixed h and e, Φ\u003csub\u003e0\u003c\/sub\u003e is exact (CODATA lists it as exact; the digits shown are truncated). Its inverse, K\u003csub\u003eJ\u003c\/sub\u003e = 2e\/h, is the Josephson constant behind the world's voltage standards. The factor 2 was confirmed in 1961 (Deaver \u0026amp; Fairbank; Doll \u0026amp; Näbauer).\u003c\/p\u003e\u003cp\u003e\u003cem\u003eHonest caveat:\u003c\/em\u003e The 2e is the pair charge, not one electron's. Flux is quantised only in superconductors, and in a thin ring it is strictly the fluxoid, not the bare flux, that comes in whole units.\u003c\/p\u003e\u003ch3\u003eOn the sticker\u003c\/h3\u003e\u003cp\u003eQuantix holds a glowing vortex swirl, with the triangular vortex lattice behind him. Printed text: \u003cstrong\u003eQUANTIX\u003c\/strong\u003e with the line \u003cstrong\u003eΦ0 = h\/2e\u003c\/strong\u003e. Pixel-art kiss-cut vinyl sticker, white, in 2″, 3″, 4″ and 6″ sizes.\u003c\/p\u003e","brand":"Printify","offers":[{"title":"2\" × 2\" \/ White","offer_id":50963654443111,"sku":"19171334107669161968","price":4.99,"currency_code":"USD","in_stock":true},{"title":"3\" × 3\" \/ White","offer_id":50963654475879,"sku":"83472158463852959964","price":6.99,"currency_code":"USD","in_stock":true},{"title":"4\" × 4\" \/ White","offer_id":50963654508647,"sku":"23780801806187144484","price":8.99,"currency_code":"USD","in_stock":true},{"title":"6\" × 6\" \/ White","offer_id":50963654541415,"sku":"27850915766850639234","price":11.99,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0596\/8746\/9159\/files\/2982148095355847160_1200.jpg?v=1793664853","url":"https:\/\/pixelatedphysics.com\/zh-hans\/products\/quantix-flux-quantum","provider":"Pixelated Physics","version":"1.0","type":"link"}