You need electrons to form Cooper pairs via coupling with an excitation (e.g., phonons). This coupling increases the resistivity.

Perhaps "good" metals (perfect conductors) lack the necessary pre-conditions for the formation of a "stable Meissner phase" presumably existing in "bad" metals?

You need electrons to form Cooper pairs via coupling with an excitation (e.g., phonons). This coupling increases the resistivity.

electron phonon interaction weak for Cu, Ag, Au

I guess in good metals the bangap is too narrow to cover superconducting condensations as follows

The main reason is that in "good" metals the interaction between conducting electrons and phonons (crystalline lattice) is poor. While superconductivity needs electron`s pairing via some interaction, like electron-phonon.

In my opinion, the band gap is transformed into superconducting condensations in superconducting states. My investigation is at odds for that electron-electron interactions are repulsive or very weak attractive in good metals. I may conclude that in good metals electron-electron interactions are too attractive to cover superconducting condensations by very narrow band gaps.

Good conventional superconductors typically need a strong electron-phonon coupling. However, a strong electron-phonon coupling in the normal (metallic) phase, means larger resistivity. The point is that a superconductor is a condensate of Cooper pairs, i.e. another phase of matter, where is not convenient for the pairs to scatter. This is because in a superconductor a gap is formed and the pairs, to be scattered, should become normal electrons overcoming this gap, something that is not energetically favourable up to a certain temperature.

The above answers seem in the correct ballpark. If one starts from the mentality that the superconducting state is a correlated phenomenon (electrons collapsing into a condensate) then starting from a good metal in which electrons are essentially uncorrelated free particles might not give you the correlations you need. But if you already have some correlations in the system, as Michael states you'll get some resistivity, then reducing temperature may change the phase that those correlations induce. No correlations, no chance of a phase transition.

I may propose Copper-Insulator-Copper as Josephson-like junction to be a superconductor at sufficiently higher temperartures than conventional BCS temeperature. Silver-Insulator-Silver is also OK.

I may propose Copper-Insulator-Copper as Josephson-like junction to be a superconductor at higher temperatures than convention BCS ones. Silver-Insulator-Silver is also OK. The reason is increasement of effective band gaps for copper.

No, it won't work. Two non-superconductors do not form a Josephson junction, the "bandgap" has nothing to do with the superconducting energy gap. The right answer was already given: in conventional superconductors the formation of condensate is due to electron phonon interaction; the same interaction is responsible for resistance in normal conductors.

We need to take into account that superconductivity is a collective phenomena, in which electrons and ion lattice play a role. At the first impact it may be not clear why a good conductor is not also a good superconductor, but if we look at the different conduction mechanisms involved will be clear. A good conductor must have a low resistivity (Ohm's law). For simplicity, we consider that a sufficient space is necessary to permit the electrons flow, so the ions must be enough spaced to avoid the collision with electrons. Instead in the superconducting state (at low temperature) is necessary that the ions are at a sufficient distance to create and mantain an interaction between two electrons (Cooper's pair). In good conductors at low temperature (4.2 K), there are weak interactions among electrons and ions (they have low resistivity) which are not able to create inter-electron actraction to overcome the Columb repulsions between two electrons.

Thanks guys. I am overwhelmed with all these comments. But I must read them carefully.

Further question: could it be answered by using symmetry arguments? I mean, in good conductors like Cu, Ag or Au the conduction band is mainly composed by states having s symmetry. Is there any requirement in the BCS theory concerning the symmetry of phonons?

Electron-phonon interaction decide about it – to create Cooper pairs (bosons) electrons have to be coupled via lattice, characterized by phonons. Materials with poor electron-lattice interaction (metals - low resistivity means good conducting properties) do not create Cooper pairs – are not superconductors.

Any material which becomes a super conductor is actually a super obstructor because all of the energy is flowing outside of the guide. c = 1/sqrt Mu*Epsilon. Because Epsilon, the permitivity is temperature dependent then when Epsilon tend to infinity c tend to zero and also the Characteristic Impedence of this medium tends to zero also. If Zo = 0 there is also a perfect short circuit. These are the reasons why we have the so called Meisner effect.

The current understanding is that electron-phonon coupling has to be strong in good metals to form Cooper pairs and become superconductors but the (bad metal-based) others such as the high temperature superconductors form electron pairs based on a different mechanism tied to antiferromagnetism or spin density waves.

Paolo. As far as I am aware, there is no requirement regarding the symmetry of phonons.

Recall that BCS theory says essentially nothing regarding the source of the constant attractive potential between the electrons. In eliashberg theory, the coupled distribution of phonon states (alpha^2 F) is used to essentially compute this attractive strength.

Since phonons are bosons, I do not see how a specific symmetry will change whether or not the electrons couple to the phonons. All of these details would be included in an extracted alpha^2F spectrum.

If one seeks to compute the alpha^2F spectrum from some DFT type calculation, then all symmetries of the phonons will be taken into account.

One needs to create an energy gap in the electronic spectrum, this can be done via strong electron-phonon or electron-electron interactions. This in turn leads to higher resistivity in the normal state.

I refer you to the book of Guy Deutscher on "New Superconductors: From Granular to High Tc". The first chapter discuss this issue in regard of BCS type superconductors.

The premise isn't even correct. Aluminum is an excellent conductor and is also superconducting at low T.

High transition temperature superconductors are investigated in analogy with BCS scheme as follows,

When I say good superconductor I also mean that it has a relatively high value of Tc. Tc of Al is rather low and its conductivity is not as good as that of Cu, Ag or Au.

About Jess's comment, I think in Al the band gap may be more larger than Cu, Au etc. so that superconductors can be possible.

After going through the comments/answers it appears that BCS theory really does not have a clear answer to the question. Naturally it is an interesting question to debate and discuss in detail. It is possible that the nature of electron phonon interaction assumed by BCS theory differs from the real nature and/or cause of such interaction. It should be noted that there are several experimental observations on metallic superconductors that are not explained by BCS theory e.g. coexistence of ferro-electricity with superconductivity.

As several people have provided the essentials for a good answer based on BCS theory, so I will just put it together in one answer. (As Graf says) Superconductivity requires conduction electrons to form Cooper pairs. In pure elemental metals, the attractive force between electrons is mediated by phonons (lattice vibrations), so you need a rather strong electron-phonon (E-P) interaction to get the Cooper pairs to form. The stronger the E-P interaction, the higher the critical temp. On the other hand, the resistance of pure metals at room temperature is dominated by the scattering of electrons by phonons. Thus, high critical temperature and high resistivity at room temperature go together. (As Paul says) The E-P interaction is very small for good room temp conductors like Cu, Ag, and Au.

Au, Ag, Cu have close packed (fcc) structure so, lattice vibration is not significant (damped). So el-phonon interaction is not pronounced....so they are bad superconductor.

@ Roger and @Sen Whatever weak e-ph interaction these elements may have, the fact that it would have non-zero value implies that Tc would have a lower (may be lower than the lowest value we know)value. Hence according to BCS theory, these elements are expected to become superconductors. Somehow the experimentalists have not been able to reach those Tc at which these elements become superconductors. What I mean is that we can not ignore the possibility that these elements too become superconductors.

Well, there are no 'good' or 'bad' superconductors; there are just

superconductors. As most answers, so far, point out: a handwaving

argument to answer this question can be based on BCS theory. A

better and more profound answer can be based on Eliashberg

theory which is valid in the normal as well as in the superconducting

state of many metals. This theory treats properly the retarded,

inelastic interaction of charge carriers with the system of exchange

bosons (in 'classical' metals phonons, the quants of lattice vibrations.)

It also includes the repulsive Coulomb interaction between the charge

carriers by a mean field approach (or by using an effective Coulomb

interaction). Thus, we have two basic interactions: the repulsive

Coulomb interaction and the inelastic interaction with exchange bosons.

Below some temperature (the critical temperature) the lifetime of

exchange bosons can become long enough so that an exchange

boson excited by one charge carrier can be absorbed by another charge

carrier, thus establishing an attractive interaction between the two charge

carriers which overcomes the repulsive Coulomb interaction. A Cooper

pair is formed and at the critical temperature we just need one Cooper

pair to exist inh order to establish the phase transition ro superconductivity.

This process, of course, requires some minimum coupling strength of the

charge carriers to the system of exchange bosons. Normal state

Eliashberg theory tells us that the resistivity of a metal increases with

increasing coupling strength to the system of exchange bosons. Thus,

it is easier for a 'bad' conductor to form Cooper pairs at higher critical

temperatures as it is for 'good' conductors. (Impurity scattering which

is unavoidable plays an additional role in the process of Cooper pair

formation depending on the material.) All this can be used to understand

why Au, Ag, and Cu do not become superconducting: in these materials

the coupling of the charge carriers to the exchange bosons (phonons)

is just too weak and/or the lifetime of the exchange bosons is just too

short. Nevertheless, all this doesn't help to understand immediately why

for instance Fe (certainly a 'bad' conductor) doesn't become superconducting.

The argument outlined above is restricted to systems which develop

metalic behavior in the normal state. In contrast, the superconducting

state of, for instance, underdoped cuprates cannot be explained on the

basis of the above argument.

This question is one of start point for the BCS theory understanding. H. Frölich writes in the introduction to his famous work (Phys. Rev., vol 79, p. 845, 1950): "One should then expect the velocity of sound to play an important role, and it is not accidental that the energy of an electron moving with the velocity of sound is of similar order as the energy per electron involved in the transition between the normal and superconducting state. Nor is it accidental that very good conductors do not become superconductors, for the required relatively strong interaction between electrons and lattice vibrations gives rise to large normal resistivity". In this work, You can find the first explanation of the problem.

The question is based on a mythical observation of limited value.

See for example from Kittel, five metals Zr, Pb, V, Nb, Mo and Al

and given below their resistivities (in units of 10-6 Ohm-cm) at 295 K, Tcs (in Kelvin) and energy gaps (in meV). Any simple correations?

Metals Resistivity Tc Eg(0)

Pb 21.0 7.2 273

V 19.9 5.38 160

Nb 14.5 9.5 305

Mo 5.3 0.92 27

Al 2.74 1.14 34

In the standard model of superconductors (BCS in this case) the effective interaction is attractive in a small range of energy (~Debye energy) near the Fermi surface, otherwise the effective interaction is repulsive everywhere. The later causes the scattering of quasi-particles in the normal state with a relaxation time that appears like Drude form of metallic resistivity. In simple Fermi-liquid metals the quasi-particle decay rate and the Drude scattering rate are small compared to the QP energy (~kT). For correlated metals with strong electron-phonon coupling the resistivity goes down to a saturated value. While the strong electron-phonon coupling is likely to produce superconducting pairing, the material may not be a bad metal in the normal state as the question is asked on this issue. Normal state transport in real materials is truly a difficult problem.

If BCS theory has the answer to this question, it is expected that the answer should be given by using appropriate relation rendered by BCS theory and the values of parameters of Cu, Ag and Au. I wonder if hand waving arguments can really be satisfying in true sense.

The answer to this question (if impurities will make a good metal superconducting)

was given a long time ago by P. W. Anderson, the famous Andersons' theorem:

in an (isotropic) s-wave superconductor the impurity concentration of non magnetic

impurities has no effect. Magnetic impurities on the other hand destroy

superconductivity rather rapidly with increasing concentration. On the other hand,

even non magnetic impurities are pair breaking in any anisotropic superconductor,

for instance in the d-wave symmetric cuprates. Consequently, just adding impurities

doesn't help.

@Nimrod Bachar, Could you pl. briefly write what reason the said book mentions in its first Chapter. I could not reach this book through all my resources. It will be useful for all the contributors.

Anderson's theorem is valid for Born limit scattering impurities up to

infinite impurity concentration.

Dear Sanjib,

Hubbard model calculations are an entirely different game. What I was

speaking about was just plain Fermi liquid theory and nothing more.

The limit to infinite impurity concentration in Anderson's theorem is just

a theoretical limit and has to be regarded as such.

I also pointed out in my first answer that even non-magnetic impurities

do affect superconductivity as they become pair breaking in anisotropic

superconductors. Thus, even in the limit I was trying to answer your first

question there is some influence of impurities as long as the system is

anisotropic.

Ewald

This generalization is easy to understand. Normally the electrons are moving among the net of atoms. This net has positive charge and electron negative so the interaction between them are attractive. This interaction is producing an electrical losses the resistivity. Silver, copper, gold are metals with low resistivity this mean that electron weekly interact with net. Surprisingly , it is not possible to obtain superconducting properties in this metal. The reason is the interaction are too weak . For superconductivity sate it is necessary obtain bosons from fermions and electron are fermions. To create bosons - cooper pair from two electrons there is need for attractive interaction. This can be only done by strong interaction between electrons and atoms net. The net are producing a phonons. When this two electrons can follow the phonons in some materials it means there are creation of superconducting state. Electrons are not disturbed phonons as well. This is only possible when the interaction between electrons and phonons are strong enough. It means bad conductor at normal sate e.g. lead which is a superconductor of type I at 7.2 K.

Well, Hubbard model calculations deal with strongly correlated systems in

contrast to Fermi liquid theory.

Cu has only electrons. A supercondensate, whose motion generates a supercurrent must have electrons and holes in parent material. Cu cannot be a superconductor.

@Shigegi: That is a good point. This is called Chapnik's rule: The superconductor must have hole carriers in the normal state. The sign of the Hall coefficient is far better a criterion than the card showing electron-phonon coupling constant. In fact many early researcher looked for superconductivity only in such materials. Also note that BCS theory being electron-hole symmetric cannot in principle explain Chapnik's rule. That is why physicists like JE Hirsch thinks that BCS is a faliure even for conventinal metallic superconductors. Now my question is what are signs of Hall coefficient of Ag and Ag in the normal state? If for these two metals carriers are also electrons, rather than holes in the normal state then my initial question is answered in terms of Chapnik's rule. But again Chapnik's rule is not a theory, but the results of experimental observation. This has led many physicists to construct hole-electron asymmetric theory of superconductivity.

Without going into details BCS theory of superconductivity is based on the fact that the attractive interaction between electrons results from virtual exchange of phonons. It is favorable to form a superconducting phase when this attractive interaction dominates the repulsive screened Coulomb interaction. However large contribution of electron –phonon interaction results in increasing of metal conductivity. So, good metals are not superconductors.

Dear all, it seem like the most answers here is, bad conductor(at ambient temp) is however more likely become supercond at temp below Tc because of ELECTRON-PHONON INTERACTION is STRONG.

But, I do not understand what actually is the meaning of electron-phonon interaction/coupling is weak or strong.

From my knowledge by semiconductor theory, conductivity is more strongly related to number of carriers. At ambient temp, bad conductor is mostly because of number of carrier is lesser if compare to good conductor, so why electron-phonon coupling have more to do to bad conductor here?

Choon-- Conductors are being considered in this thread, not semi-conductors.

@Roger, thanks for the answer. I thought it would be the same way in estimation, as in my book, it is using similar equation for conductor and semiconductor.

I just wander is there got something to do with the number of conducting electrons (or carriers)

if we see from the element table, the conductivity is increasing from group IV to group VI, but the Tc is low (relatively) for group IV, then high for group V, and low again for group VI... this i broght my mind to electron configuration or electronic state

The BCS theory was based for materials with spherical Fermi surfaces, such as Cu, Ag, Au, but such metals are not superconductors. So, the BCS theory is not valid for metals with kvazi-spherical Fermi surfaces. Superconducting materials 1) must have degenerated free electron or hole gas, and 2) near the Fermi energy level there must be the overlapping sub-bands of charge density of states. These density of state sub-bands separate at critical temperature Tc, and make the energy gap between two overlapping sub-bands. As can be shown from the Landau second order phase transition, the state of material with energy gap is more energetically advantaged (the free Gibbs energy is smaller) at low temperatures than when without the gap. It, may be, that interaction forces between the electron pairs, coupled on the Pauli principle in degenerate electron gas, are stonger when there are no unpaired on the base of Pauli principle electrons. It can be pointed that these electron pairs in principle are not bosons, they are described by Fermi statistics..

Let me restate that all these arguments are more or less qualitative. These are some how clubbed with BCS theory to indicate that BCS theory explains this observation which clearly not true. These arguments have no bearing from mathematical formulation and its relation with BCS theory. In fact people should keep in mind that there are very strong experimental evidence to establish that BCS theory is not the right theory even for metallic superconductors.

https://www.researchgate.net/publication/236869920_Questioned_BCS-I

In this respect one may find that BCS theory or similar other theories of even High T superconductivity have intrinsic problems. Their basic premises do not agree with physical realities of conduction electrons at low T.

http://www.scribd.com/doc/110441679/Intrinsic-Problems-Superfluid-Theories

Article Questioned_BCS-I

R.Asokamani, Tamil Nadu Academy of sciences, chennai,India

BCS theory has been found to work well with the conventional /Low Tc superconductors . In this frame work ,the electron -phonon coupling constant decides the superconducting transition temperature. Its value calculated using band structure calculations or from tunneling studies shows that the value of coupling constant to be small for good conductors . This when substituted in McMillans formula shows a very low Tc for weakly coupled systems.

The electron -phonon coupling constants extracted from experiments and calculated theoretically are tabulated in the books edited by R.D.Parks and that of Grimvall on electron-Phonon interaction or Thermophysical properties.

Of course, BCS theory assumes a spherical Fermi surface , which is an approximation.

BCS theory, as it is well known cannot be applied to strongly coupled systems and a unified theory should be found which can be applied to all classes of superconductors ( Cuprates , ferro nictides) which should reduce to BCS under limiting condition.

Regarding Hall coefficient of Au, it is known that many metals show a positive Hall

coefficient . one should know about the Hall coefficient of pure semiconductors.

Hall coefficient studies alone cannot give the nature of carriers .

Some of our papers on the calculation of superconducting behaviour using electron - phonon coupling mechanism performed for several systems may be useful.

In what follows from the basic principles that we follow in accepting a given model, the model should explain all experiments at quantitative scale. However, it is strange that we keep arguing that BCS theory is the right theory for conventional (i.e. Metallic superconductors ) superconductors, while this theory does not explain several experimental observations observed in recent times. This has been elegantly discussed by Hirsch (Phys. Scr. 80 (2009) 035702). It is well evident that this theory does not explain the coexistence of superconductivity and ferroelectricity, as shown in

https://www.researchgate.net/publication/236869920_Questioned_BCS-I

Further it is also evident BCS theory and similar other theories of superconductivity have intrinsic problems with physical realities of the low temperature states of electron fluid in different systems.

http://www.scribd.com/doc/110441679/Intrinsic-Problems-Superfluid-Theories

Consequently, these theories can not render a clear, complete, and experimentally consistent account of the superconducting state in spite of their mathematical accuracy. If researchers are interested to have unified theory of superconductivity, I appeal to them to abandon their bias for BCS theory as the right theory of conventional superconductors and consider the newer ideas for this purpose.

Article Questioned_BCS-I

I agree with Dr.Yaetndra jain regarding his statement that BCS theory does not fully explain the experimental observations.

It is well known that our basic understanding that magnetism will kill superconductivity and now Fe containing systems are superconductors.hence, new theories are needed .However, energy gaps for several conventional systems have been obtained from BCS theory and the agreement has been reasonable.

Energy gap is not only resulted from the electron-phonon interaction (as presumed in BCS theory) or similar interaction between electron and other possible quasi-particle excitations (as proposed in other theories of superconductivity) but is also observed due to an inter-play between zero-point repulsion among quantum particles in their ground state and their natural attraction. All theories of superconductivity totally ignore this reality. It is the basic reason that none of these theories succeeded to provide a unified theory of superconductivity or a theory for a class of superconductors. It is strange that every many body theorist admits that liquid helium-3 and liquid helium-4 do not become solid under their own vapour pressure even at T=0 because of the zero-point repulsion among helium atom but no conventional theory of these liquids examines /underlines the role of this force in understanding the low temperature behaviour of these quantum liquids. I do not know why ?, these theorists do not wish to consider to debate the merits and demerits of theories which consider the role of this force which exclusively emerges at the low temperatures when quantum particles occupy their ground state. Development of Science can not proceed if the majority decides not to accept the minority opinion in spite of its accuracy. I appeal to other physicists to look into this problem seriously. Conventional theorists who have been the referees to the theories based non-conventional approach did not allow the publication of these theories in mainstream journals and do not refer these works in their publications because the non-conventional theories find no common grounds with conventional theories. I would reiterate that the basic premises of conventional microscopic theories of superconductivity and superfluidity have serious contradictions with the basic realities of the low temperature states of the quantum fluids and they can never provide complete, clear and experimentally consistent microscopic account of superconductivity or superfluidity. It appears that conventional theorists would not come forward to accept this fact unless other physicists come forward to accept it.

In spite of the fact that the question is concrete (for the superconductivity of bad and good metals) it appears to be more general. When the BCS theory is constructed very small part of type 2 superconductors have been discovered. Today we have several large groups of type 2 superconductors and among them even iron containing compounds. Probably more general theory incorporating not only electon-phonon interactions but other coupling mechanisms will succeed to explain the existing open questions.

The higher the room temperature resistivity , the possibilty of finding superconductivity

is better, as you have written.

We have to look for scaling laws.

I recall my talks which I gave in 1984 on superconductivity at ILL and again on properties of materials in 2009.

If we feel that we can do some work on this, We can do so.

I forgot to add that my my mail is general and is also addressed to Dr.Tapan Chatterji of ILL .

because superconductivity is evil and only bad metals are good at it.

Although, you do know that the highest Tc superconductors are Cu based, right? So obviously Cu is just pretending to be good, while practicing the dark arts covertly.

By the way, a Phonon mediated state has been ruled out for High Tc Superconductors a while ago. Experiments were done using isotopes substituted in the structure and the Superconductivity parameters did not change (Tc, Hc, etc...). Since increasing the mass of the atoms will change the phonon states, if High Tc superconductivity were phonon mediated like BCS superconductors, then it would have a large effect on the superconducting properties. Such experiments were done on BCS superconductors in the past to help confirm the BCS theory.

Please read the answer to this question in my recently uploaded paper, titled, 

'Absence of superconductivity in gold, silver and copper, etc

and Jain’s theory of superconductivity'

on this site as

https://www.researchgate.net/publication/264121654

Article Absence of superconductivity in gold, silver and copper, etc...

The observation is not sufficiently specific, because in general all metals are good enough electric conductors.  The three metals in question, i.e. Cu, Ag and Au, are all of valency1 with nearly total cancellation of the electron-phonon interaction in the superconductive state, see my three papers attached to ResearchGate.

Please read our paper attached to this;

Dear Drs  Zheng and Koo

You may both be right in concluding what you claim in your papers. However, it is my humble submission that the basic assumption of BCS theory which you use in your works (with partly modified presumptions) is wrong; it is wrong because it is inconsistent with basic physical realities of low temperature states of conduction electrons where they are close to superconducting state or they are part of the superconducting state.  This fact has not only been unequivocally concluded in my following paper

http://www.scribd.com/doc/110441679/Intrinsic-Problems-Superfluid-Theories

but is also evident from the existence of electron bubble in liquid He-3 and liquid He-4 where it occupies its ground state or one of the low energy states when excited to such states of the bubble.

Unfortunately, people working in the field seems to have a firm opinion that BCS theory is the only theory whose frame work can provide final theory of superconductivity and in what follows they do not even refer the work which concludes basic problems of BCS theory.     I do not know but possibly because of this reason that my first quantization theory of superconductivity

http://www.scribd.com/doc/110681115/First-Quantization-Theory-of-Superconductivity

and my above paper could not find place in the reference lists of your papers. Else, it is also possible that you find fundamental flaws with these works.    If it is so, I would be greatly indebted, if you kindly report these flaws at these pages of discussion on this question which you have tried to answer.     This will greatly help me in realising my mistake and if possible to correct it.    This also necessary for other physicists to know what is right and what is wrong.      As far as what is concluded by several experiments which have been performed in last two decades BCS theory is a theory of past.      It has basic flaws in respect of its consistency with low temperature states of conduction electrons.

I also request other physicists to let people understand by your efforts in concluding where I am wrong in my conclusions of my first paper and where my theory of superconductivity (second paper) has errors.

Let me further add that second quantization approach was adopted to formulate the theories of widely different many body systems from the beginning. First quantization was abandoned because it needs separation of 3N degrees of freedoms of N particle system which, if tried, would be an impossible task. Since the problem was complex, very eminent physicists and mathematicians worked on all these problems. Typical of these systems were liquid He-4, liquid He-3, electron fluid in electrical conductors and many nucleon systems in atomic nucleus. All these systems exhibit superfluidity (superconductivity is also superfluidity of electrically charged electrons).

Inadvertently, it was not realised that basic assumptions of the approach have inconsistency with real physical states of the these systems in their low energy (low temperature) states. In addition the second quantization approach assumes that the physics of any physical system is decided by its energy spectrum; the arrangement of particles is of no consequence. In the process, it was not realised (once again inadvertently) that low energy (low temperature) behaviour (i.e. superfluidity) of these systems differs from normal state behaviour basically for the fact that particles in the former case have ordered arrangement of particles as demonstrated by several recent experiments; certainly, there are other reasons too.

In what follows, one finds that second quantization approach could not help in concluding the complete physics of none of these systems with necessary clarity of physical arguments and quantitative consistency with experiments. Interesting this demonstrated by the fact that no such theory (including BCS theory of superconductivity) provides complete picture with necessary clarity and agreement with experiments, although, thousands of papers have been published. However, people used second quantization because it so happened that no effort was made to explore the possibility to make first quantization approach suitable for many body systems. Naturally, people who have been using second quantization to determine the physics of many body quantum systems have done their best to discover the origin of superfluidity and related aspects and deserved the honour and rewards they have been conferred. I salute their efforts.

Somehow, my destiny forced me to try my efforts by using first quantization for which I devoted more than twenty five years. But when I succeeded in developing the desired mechanism and in concluding the long awaited microscopic theories of liquid He-4 (published in Amer. J. Conden. Matter. Physics and available on research gate site) and of superconductivity/liquid He-3) and related works available at research gate, I have been having extremely sad experiences. I am pained to state that people who have been working in the field have been very unkind in many different ways.  Nevertheless I have no regret that I tried non-conventional approach in place of conventional one which could have provided me at least a pleasure of publishing some papers. I am sure that people would accept my works in very near future.

Dear Physicists

A friend marked my above two responses with dislikes apparently because he found mistakes in these responses.   However, this does not let others understand the errors and mistakes and unfortunately he has no way to find these mistakes due to his anonymous status.     Hence to this effect, I sincerely request every one that if you have reason to disagree with me please write comments with reasons so that I get an opportunity to understand my mistakes.  I believe that in the field of research every body is a student of the subject and he can make mistakes.   It is by nature of the research that we try to develop new understanding and correct the conventional understanding and it is natural that in this process we commit mistakes.   No body makes mistakes intentionally.     So please feel free to write your reasons for your dislikes and oblige me to give me an opportunity to correct my mistakes.   I would always feel grateful of your valuable comments.   

These metals, Cu, Ag, Au, among others have very low electron-phonon coupling. And, you know, the most part of pure metals are BCS superconductors which have as a mechanism to form a Cooper pair. So, independently these metals not are known to exhibit the superconducting state. But, if you are taking into account multi layers of these metals, the "history" will change.

Please refer my paper attached to this.

Please read my paper attached to this message.

Please read my paper related to high transition temperature superconductors attached to this message.

Please refer my paper related zero Coulomb repulsion in most metals.