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Zhao, Li; Lan, Tian‐Wey; Wang, Kuen-Jen; Chien, Chin-Wen; Hung, Tsu‐Lien; Luo, Jianxi; Chao, Wei-Hsiang; Chang, Chung‒Chieh; Chen, Yang‐Yuan; Wu, Maw–Kuen; Martin, C.

doi:10.1103/physrevb.86.064408

Cited by 10 publications

(2 citation statements)

References 30 publications

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“…In the same sense that without the unifying framework of quantum dynamics, the different quantum phenomena -such as the blackbody spectrum, the photoelectric effect, the hydrogen-atom spectrum, superconductivity, etc.would appear unrelated phenomena that somehow involve the same constant .7 Counter examples are the MOND theories discussed inBabichev & al. (2011), which adds a length scale, and inZhao & Famaey (2012), based on a suggestion inBekenstein (2011), which adds a velocity constant.8 TeVeS(Bekenstein 2004), and its NR limit, is a counterexample: it does have additional dimensionless parameter(s). TeVeS does not tend to GR in the mere limit a0 → 0, and to make it agree with various high-acceleration constrains, one of these constants is forced to be much different from unity.…”

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confidence: 99%

MOND laws of galactic dynamics

Milgrom¹

2013

Monthly Notices of the Royal Astronomical Society

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MOND predicts a number of laws that galactic systems should obey irrespective of their complicated, haphazard, and mostly unknowable histories -as Kepler's laws are obeyed by planetary systems. The main purpose of this work is to show how, and to what extent, these MOND laws follow from only the paradigm's basic tenets: departure from standard dynamics at accelerations a a 0 , and space-time scale invariance in the limit a ≪ a 0 . Such predictions will be shared by all MOND theories that embody these premises. This is important because we do not know which of the existing MOND theories, if any, is a step in the right direction. In the Newtonian-dynamics-plus-darkmatter paradigm, the validity of such clear-cut laws -which tightly constrain baryons, 'dark matter', and their mutual relations -is contrary to expectations. Subject headings:1 Here, and in many other instances, when I refer to 'accelerations' in comparison with a0, I mean 'all quantities with the dimensions of acceleration'. This is analogous to relativity reducing to ND when all quantities with the dimensions of velocity are much smaller than the speed of light (not only velocities, but also, e.g. the square root of the gravitational potential).

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confidence: 99%

MOND laws of galactic dynamics

Milgrom¹

2013

Monthly Notices of the Royal Astronomical Society

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“…In addition to the polaronic oxygen holes, there are electronlike free carriers which could condense into supercarriers through interband scattering. The pairing symmetry of the two-carrier system may be an extended s-wave with eight line nodes [28]. Now we can calculate the total isotope exponent α using Eqs.…”

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confidence: 99%

Isotope Effects and Possible Pairing Mechanism in Optimally Doped Cuprate Superconductors

Zhao

Kirtikar²,

Morris³

2020

Peking University-World Scientific Advanced Physics Series

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We have studied the oxygen-isotope effects on Tc and in-plane penetration depth λ ab (0) in an optimally doped 3-layer cuprate Bi1.6Pb0.4Sr2Ca2Cu3O10+y (Tc ∼ 107 K). We find a small oxygenisotope effect on Tc (αO = 0.019), and a substantial effect on λ ab (0) (∆λ ab (0)/λ ab (0) = 2.5±0.5%). The present results along with the previously observed isotope effects in single-layer and doublelayer cuprates indicate that the isotope exponent αO in optimally doped cuprates is small while the isotope effect on the in-plane effective supercarrier mass is substantial and nearly independent of the number of the CuO2 layers. A plausible pairing mechanism is proposed to explain the isotope effects, high-Tc superconductivity and tunneling spectra in a consistent way.The pairing mechanism responsible for high-T c superconductivity is still controversial. In conventional superconductors, a strong effect of changing ion mass M on the transition temperature T c implies that lattice vibrations (phonons) play an important role in the microscopic mechanism of superconductivity. An isotope exponent α (= −d ln T c /d ln M ) of about 0.5 is consistent with the phonon-mediated BCS theory. A nearly zero oxygen-isotope effect (α O ≃ 0.03) was earlier observed in a double-layer cuprate superconductor YBa 2 Cu 3 O 7−y which is optimally doped (T c ∼ 92 K) [1,2]. Such a small isotope effect might suggest that phonons should not be important to the pairing mechanism. On the other hand, large oxygen-isotope shifts were later observed in several underdoped cuprate superconductors [3][4][5][6][7][8][9]. Further, three indirect experiments have consistently demonstrated that the difference in the hole densities of the 16 O and 18 O samples is smaller than 0.0002 per Cu site [7][8][9]. Moreover, a quantitative data analysis on the isotopeexchanged YBa 2 Cu 3 O 6.94 [10] suggested that there is a negligible oxygen-isotope effect on the supercarrier density n s .Since muon-spin rotation experiments [11] showed that T c is approximately proportional to n s /m * * ab in deeply underdoped cuprates (where m * * ab is the in-plane effective supercarrier mass), a large oxygen-isotope shift of T c observed in this doping regime should arise from a large oxygen-isotope effect on m * * ab . Indeed, several independent experiments [7-9,12] have consistently demonstrated that both the average supercarrier mass m * * and the in-plane supercarrier mass m * * ab strongly depend on the oxygen isotope mass in underdoped cuprates. Such an unconventional isotope effect suggests that there exist polaronic charge carriers, which are condensed into supercarriers in the superconducting state. This appears to give a support to a theory of (bi)polaronic superconductivity [13]. On the other hand, within this theory, it is difficult to explain a small isotope shift of T c and a large reduced energy gap (i.e., 2∆(0)/k B T c > 6) observed in optimally doped cuprates where single-particle excitation gap vanishes above T c [14]. Therefore, an alternative theoretical approach is r...

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