Conventional vs. Unconventional Superconductors, Michael R. Norman

“To appreciate these issues, we need to first understand what superconductors are all about, and how unconventional ones differ from their more conventional counterparts. Superconductors are not only perfect conductors (their electrical resistance drops precipitously to zero below a transition temperature Tc), but also exhibit the so-called Meissner effect (6), where they expel magnetic fields. As noted by Fritz London (7), this implies that electrons in superconductors behave in a collective manner. Bosons, which have integer values of a fundamental property known as ‘spin’, can behave in this fashion, whereas electrons, which are fermions that have half-integer spins, typically do not. This apparent contradiction was resolved by Leon Cooper in 1956 (2) who demonstrated that the presence of even an arbitrarily small attractive interaction between the electrons in a solid causes the electrons to form pairs. Because these ‘Cooper pairs’ behave as effective bosons, they can form something analogous to a Bose-Einstein condensate. Rather than being real-space molecules, however, Cooper pairs consist of electrons in time- reversed momentum states and consequently have zero center-of-mass momentum. Because a pair of identical fermions is antisymmetric with respect to the exchange of one fermion with another, the spin and spatial components of the Cooper pair wavefunction must have opposite
exchange symmetries. Thus these pair states are either spin singlets with an even parity spatial component, or spin triplets with odd parity. The spin singlet pair state with an isotropic spatial component (s-wave) turns out to be the one realized in conventional superconductors (3). Despite the fact that electrons repel each other because of the Coulomb force, at low energies there can be an effective attraction resulting from the electron-ion interaction. To understand this, note that a metal is formed by mobile electrons detaching themselves from the atoms that
form the crystalline lattice (these atoms then become positive ions). Such a mobile electron attracts the surrounding ions because of their opposite charge. When this electron moves, a positive ionic distortion is left in its wake. This attracts a second electron, leading to a net
attraction between the electrons. This mechanism works because the ion dynamics is slow compared to the electrons, a consequence of the fact that the ions are much heavier than the electrons. However, the interaction at shorter times becomes repulsive because of the Coulomb
interaction between the electrons; this retardation is what is responsible for limiting Tc (8). Up until the discovery of cuprates, the highest known Tc was only 23K.”

OBSERVATION: We must be thankful to all great thinkers who inhabit our planet. Questions arise when pondering ideas about materials that redefine what we know about matter. What are the limits of the physical? We live in an era of great scientific expansion, and the future will allow us to observe the abstract nature of the human imagination in retrospect. The known, the unknown, that which will be known…………………


I say that one must be a seer, make oneself a seer. The poet makes himself a seer by a long, prodigious, and rational disordering of all the senses. Every form of love, of suffering, of madness; he searches himself, he consumes all the poisons in him, and keeps only their quintessences. This is an unspeakable torture during which he needs all his faith and superhuman strength, and during which he becomes the great patient, the great criminal, the great accursed – and the great learned one! – among men. – For he arrives at the unknown! Because he has cultivated his own soul – which was rich to begin with – more than any other man! He reaches the unknown; and even if, crazed, he ends up by losing the understanding of his visions, at least he has seen them! Let him die charging through those unutterable, unnameable things: other horrible workers will come; they will begin from the horizons where he has succumbed.”

OBSERVATION: The intensity and difficulty of life endured by those closely in touch with the world and the self is evident in this excerpt from Rimbaud. Perhaps it is necessary to simply understand contributions by artists, rather than attempting to dissect and interpret them. Perhaps true art exists, independent of criticism. Maybe true art is meant to be experienced, somehow reliving the intense moment of intuition and expression drawn from the life force of the artist.


Berlin, Isaiah, Russian Thinkers, Hogarth Press, Viking Press, 1978.

The Hedgehog and the Fox: “A queer combination of the brain of an English chemist with the soul of an Indian Buddhist.” E M de Vogue

page 42…..”There is a particularly vivid simile (War and Peace, epilogue, part 1, chapter 2) in which the great man is likened to the ram whom the shepherd is fattening for the slaughter. Because the ram duly grows fatter, and perhaps is used a a bell-wether for the rest of the flock, he may easily imagine that he is the leader of the flock, and that the other sheep go where they go solely in obedience to his purpose. He thinks this and the flock may think it too. Nevertheless the purpose of his selection is not the role he believes himself to play, but slaughter–a purpose conceived by beings whose aims neither he nor the other sheep can fathom.”

OBSERVATION: Berlin is a thinker who helps us see, and understand beyond the surface that presents itself. Perception, the enlightened activity of insight, and the ability to recognize the function of words, conceptualization, and communication assist us in the quest to understand who and what we are. As human beings, it is our duty to know, to think and ponder. Perception, point of view, content, all drive understanding. How effectively and accurately we use these various conceptual tools, helps us truly understand the nature of reality, and our individual part in the human collective.

WIRE: 2011



OBSERVATION: ” Images can transport our thought process, requiring perception, observation, contemplation, interpretation, reaction, conclusion. Art can expose the inner self, causing the individual observer to show his or her own fears, beliefs, intellect. Perhaps, art that is worthy of the name forces the participant into this intimate relation between the art and the self, somehow transforming conscious activity into uncharted conceptual spaces, activating new neural pathways.”