电子之间本来相斥，为什么在超低温下却能两两“手拉手”组成库珀对通过晶格？
Electrons normally repel — why at very low temperature do they pair up as Cooper pairs via the lattice?
一个电子经过正离子晶格时会把格子微微拉近，造成局部正电荷聚集，吸引另一个电子过来。这个“声子当红娘”的间接吸引，在低温下胜过直接排斥，于是电子成对、无阻力地流动。
An electron nudges the positive lattice inward, creating a local positive patch that attracts a second electron. This phonon-mediated attraction wins over direct repulsion at low temperature, so electrons pair and flow without resistance.
难度 专业 · 适合 大众
CC BY 4.0 · 已核验 · Verified 2026-11-04
来源 · Source
J. Bardeen、L. N. Cooper 与 J. R. Schrieffer,《Theory of Superconductivity》,Physical Review 108, 1175,1957 (DOI: 10.1103/physrev.108.1175)
J. Bardeen, L. N. Cooper & J. R. Schrieffer, 'Theory of Superconductivity', Physical Review 108, 1175, 1957, DOI: 10.1103/physrev.108.1175
独立核验依据 · Independent verification: 核验依据 1 Crossref DOI 10.1103/physrev.108.1175
#库珀对 #声子 #BCS
SQUID 这种超灵敏磁强计，为什么能测到人体大脑活动产生的微弱磁场？
Why can a SQUID magnetometer detect the faint magnetic fields from human brain activity?
SQUID 利用超导环里磁通的量子化，对极微小的磁场变化都能产生可测的电压。大脑的神经元电流只有极弱的磁场，普通仪器测不到，SQUID 却灵敏到能分辨。
A SQUID exploits quantization of magnetic flux in a superconducting loop, turning tiny field changes into measurable voltage. Neuronal currents make only a faint field, but a SQUID is sensitive enough to resolve it.
难度 专业 · 适合 大众
CC BY 4.0 · 已核验 · Verified 2026-10-04
来源 · Source
Michael Tinkham 著《Introduction to Superconductivity》（超导电性导论）
Michael Tinkham, Introduction to Superconductivity
独立核验依据 · Independent verification: 核验依据 1 ISBN 978-0-486-134727-2 (2012, Dover)
#SQUID #磁强计 #脑磁
第一类和第二类超导体，为什么只有第二类能扛住强磁场去做强磁体？
Why can only type-II superconductors withstand strong fields to make powerful magnets?
第一类超导体一碰到较强磁场就整体失去超导（迈斯纳态被破）。第二类允许磁场以“量子磁通线”的形式局部穿入，只要不超过上限就能继续超导，所以能做核磁共振和聚变堆里的大磁体。
Type-I loses superconductivity entirely above a modest field. Type-II lets magnetic flux enter as quantized vortices while staying superconducting below an upper limit, enabling the strong magnets in MRI and fusion.
难度 专业 · 适合 大众
CC BY 4.0 · 已核验 · Verified 2026-11-03
来源 · Source
A. A. Abrikosov, 《On the Magnetic Properties of Superconductors of the Second Group》, Soviet Physics JETP 5, 1174 (1957)
A. A. Abrikosov, 'On the Magnetic Properties of Superconductors of the Second Group', Soviet Physics JETP 5, 1174 (1957)
独立核验依据 · Independent verification: 核验依据 1 INSPIRE 标识 inspire:9138：On the Magnetic Properties of Su
#第一类 #第二类 #磁通
为什么超导磁体可以用很小的电源「充」出持续数年的强大磁场?
How can a superconducting magnet hold a powerful field for years after being charged by a small power supply?
超导线圈没有电阻,电流在其中流动几乎不消耗能量。建磁场时电源缓慢给线圈充电,达到目标电流后用超导开关把线圈两端短接,形成一个无阻闭合回路——电流便在这圈超导线里持续环流,磁场随之保持。衰减率主要取决于接头残余电阻与机械微扰,好的MRI或核磁共振谱仪磁体每年电流衰减可低至百万分之一量级,因此只需小电源完成「充电」,之后即可撤去,这正是常规铜线圈无法企及的。
A superconducting winding has no resistance, so current flows without dissipation. The supply slowly ramps the coil to its target current, then a superconducting switch shorts the terminals into a closed resistanceless loop; the current keeps circulating and the field persists. Decay is dominated by joint residual resistance and mechanical disturbances — good MRI and NMR spectrometer magnets lose on the order of one part per million per year. Only a small supply is needed for charging, something copper coils can never match.
难度 专业 · 适合 大众
CC BY 4.0 · 已核验 · Verified 2026-10-04
来源 · Source
Wilson,《Superconducting Magnets》,Oxford University Press,1983
M. N. Wilson, Superconducting Magnets, Oxford University Press, 1983
独立核验依据 · Independent verification: 核验依据 1 ISBN 9780198548102 (1983)
#超导磁体 #持久电流 #应用超导
磁悬浮列车用的超导磁体，为什么通常要泡在液氦或液氮里？
Why are the superconducting magnets in maglev trains usually soaked in liquid helium or nitrogen?
超导只在足够低的温度下才出现，液氦（约 -269℃）和液氮（约 -196℃）能提供这种极冷环境。保持低温，磁体才能零电阻地产生强大稳定的磁场。
Superconductivity needs very low temperature, which liquid helium (~-269°C) or nitrogen (~-196°C) supplies. Staying cold lets the magnet carry huge current with zero resistance.
难度 进阶 · 适合 初中(12-15)
CC BY 4.0 · 已核验 · Verified 2026-10-04
来源 · Source
Michael Tinkham 著《Introduction to Superconductivity》（超导电性导论）
Michael Tinkham, Introduction to Superconductivity
独立核验依据 · Independent verification: 核验依据 1 ISBN 978-0-486-134727-2 (2012, Dover)
#液氦 #液氮 #磁悬浮
为什么“高温超导”（如能用液氮冷却的那类）的发现，让超导离日常应用近了一大步？
Why did 'high-temperature' superconductors (coolable by liquid nitrogen) bring superconductivity much closer to everyday use?
以前超导要液氦，又贵又难伺候；液氮却便宜又常见。能用液氮冷却，意味着超导电缆、磁体和器件在成本和工程上更容易推广。
Old superconductors needed expensive, fussy liquid helium; liquid nitrogen is cheap and common. Cooling with it makes superconducting cables and magnets far more practical to deploy.
难度 进阶 · 适合 大众
CC BY 4.0 · 已核验 · Verified 2026-11-03
来源 · Source
J. G. Bednorz 与 K. A. Müller, 《Possible High-Tc Superconductivity in the Ba-La-Cu-O System》, Zeitschrift für Physik B 64, 189 (1986)
J. G. Bednorz & K. A. Müller, 'Possible High-Tc Superconductivity in the Ba-La-Cu-O System', Zeitschrift für Physik B 64, 189 (1986)
独立核验依据 · Independent verification: 核验依据 1 INSPIRE 标识 10.1007/BF01303701：Possible high Tc supercond
#高温超导 #液氮 #应用
超导体的“临界温度”是什么意思——超过它为什么就“不超导”了？
What is a superconductor's critical temperature — why does it stop superconducting above it?
临界温度是材料从“零电阻”变回普通金属的温度界线。低于它时电子成对、完美导电；一旦升温超过临界值，这对“解散”，电阻就回来了。
The critical temperature is the line below which a material has zero resistance. Below it electrons pair up and conduct perfectly; above it the pairs break and ordinary resistance returns.
难度 进阶 · 适合 大众
CC BY 4.0 · 已核验 · Verified 2026-10-04
来源 · Source
Michael Tinkham 著《Introduction to Superconductivity》（超导电性导论）
Michael Tinkham, Introduction to Superconductivity
独立核验依据 · Independent verification: 核验依据 1 ISBN 978-0-486-134727-2 (2012, Dover)
#临界温度 #零电阻 #相变
超导的迈斯纳效应说明了什么？
What does the Meissner effect of superconductors show?
迈斯纳效应指超导体在转变温度下会把内部磁场完全排出，表现为完全抗磁。这说明超导态不只是零电阻，更是一个具有宏观量子相干的态。它使超导体能悬浮在磁体之上。
The Meissner effect means a superconductor below its transition temperature expels all internal magnetic field, showing perfect diamagnetism. This shows the superconducting state is not just zero resistance but a macroscopically quantum-coherent state. It lets a superconductor levitate above a magnet.
难度 进阶 · 适合 大众
CC BY 4.0 · 已核验 · Verified 2026-10-03 · 4 条独立证据
来源 · Source
Halliday, Resnick, Walker,《Fundamentals of Physics》第10版,Wiley,2013
David Halliday, Robert Resnick, Jearl Walker, Fundamentals of Physics, 10th ed., Wiley, 2013
独立核验依据 · Independent verification: 核验依据 3 angusrobertson.com.au
#超导 #迈斯纳效应 #抗磁
磁通钉扎为什么能让一小块超导体“卡”在半空，不掉下来？
Why does flux pinning let a small superconductor hang frozen in mid-air?
第二类超导体里的缺陷会“钉住”穿过的磁通线。要移动它，就得强行把磁通线从缺陷里拽出来，需要很大外力，于是它就被稳稳地悬在磁场中的某个位置。
Defects in a type-II superconductor pin the flux lines passing through. Moving it means tearing those lines free, which takes great force, so it stays locked in place within the magnetic field.
难度 进阶 · 适合 大众
CC BY 4.0 · 已核验 · Verified 2026-10-04
来源 · Source
Michael Tinkham 著《Introduction to Superconductivity》（超导电性导论）
Michael Tinkham, Introduction to Superconductivity
独立核验依据 · Independent verification: 核验依据 1 ISBN 978-0-486-134727-2 (2012, Dover)
#磁通钉扎 #悬浮 #缺陷
第一类和第二类超导体在混合态行为上的核心区别是什么?决定这一区别的关键参数是什么?
What distinguishes type-I from type-II superconductors in their mixed-state behavior, and which key parameters decide this distinction?
第一类超导体只有一个临界场,超过后迈斯纳效应完全破坏;第二类超导体存在下临界场 Hc1 和上临界场 Hc2,在两者之间磁场以量子化磁通涡旋的形式部分穿透体内。区别由京茨堡-朗道参量 κ = λ/ξ 决定:κ < 1/√2 为第一类,κ > 1/√2 为第二类。实用超导材料如 NbTi 和 Nb3Sn 都是第二类,依靠钉扎磁通涡旋来承载大电流并保持零电阻。
A type-I superconductor has a single critical field above which superconductivity collapses entirely, whereas a type-II has lower and upper critical fields Hc1 and Hc2 between which flux penetrates as quantized vortices. The distinction is set by the Ginzburg–Landau parameter κ = λ/ξ: κ < 1/√2 gives type-I, κ > 1/√2 gives type-II. Practical conductors such as NbTi and Nb3Sn are type-II, relying on vortex pinning to carry large currents at zero resistance.
难度 进阶 · 适合 大众
CC BY 4.0 · 已核验 · Verified 2026-10-04
来源 · Source
Tinkham《Introduction to Superconductivity》第5章;Abrikosov, Sov. Phys. JETP 5, 1174 (1957)
Tinkham, Introduction to Superconductivity, ch. 5; Abrikosov, Sov. Phys. JETP 5, 1174 (1957)
独立核验依据 · Independent verification: 核验依据 1 ISBN 978-0-486-134727-2 (2012, Dover)
#磁通涡旋 #金兹堡-朗道理论
迈斯纳效应为什么说明超导不只是「零电阻」,而是完全抗磁?
Why does the Meissner effect show superconductivity is more than zero resistance — it is perfect diamagnetism?
如果超导只是「电阻为零的理想导体」,那么按电磁感应规律,降温进入超导态之前就存在的磁场磁通应当被「冻结」保留在体内。但1933年迈斯纳和奥克森菲尔德的实验显示:无论先加磁场还是先降温,只要进入超导态,体内磁感应强度一律被排空为零,磁场被挤到表面薄层内。这种与历史路径无关的完全抗磁,只能用超导基态的热力学性质解释,是判断真正超导电性的标志之一,磁悬浮演示正是它的直观体现。
If a superconductor were merely a perfect conductor with zero resistance, electromagnetic induction would freeze in any magnetic flux present before cooling. But in 1933 Meissner and Ochsenfeld showed that regardless of whether field-cooled or zero-field-cooled, once the material goes superconducting the interior flux is expelled to zero, confined to a thin surface layer. This path-independent perfect diamagnetism follows from the thermodynamics of the superconducting ground state, is a hallmark used to identify genuine superconductivity, and powers the familiar levitation demonstrations.
难度 进阶 · 适合 高中(15-18)
CC BY 4.0 · 已核验 · Verified 2026-10-04
来源 · Source
Tinkham,《Introduction to Superconductivity》第2版,McGraw-Hill,1996
M. Tinkham, Introduction to Superconductivity, 2nd ed., McGraw-Hill, 1996
独立核验依据 · Independent verification: 核验依据 1 ISBN 978-0-486-134727-2 (2012, Dover)
#超导 #迈斯纳效应 #抗磁性
为什么有的金属冷到零下两百多度，电流流过它却一点也不发热？
Why does some metal, when cooled to below -200°C, carry current without getting hot at all?
因为那种极冷让金属变成了“超导体”，电流可以毫无阻碍地流过去，不浪费一点能量变成热。就像小珠子在光滑到底的轨道上滚，永远不减速。
At that extreme cold the metal becomes a 'superconductor', so current flows with zero resistance and no energy wasted as heat — like a bead rolling on a perfectly smooth track, never slowing.
难度 入门 · 适合 幼儿(3-6)
CC BY 4.0 · 已核验 · Verified 2026-10-04
来源 · Source
Michael Tinkham 著《Introduction to Superconductivity》（超导电性导论）
Michael Tinkham, Introduction to Superconductivity
独立核验依据 · Independent verification: 核验依据 1 ISBN 978-0-486-134727-2 (2012, Dover)
#超导体 #零电阻 #低温