Back to Search
Start Over
Multifractal metal in a disordered Josephson junctions array
- Source :
- Digital.CSIC. Repositorio Institucional del CSIC, instname
- Publication Year :
- 2017
- Publisher :
- American Physical Society, 2017.
-
Abstract
- 10 pags., 9 figs., 1 tab.<br />We report the results of the numerical study of the nondissipative quantum Josephson junction chain with the focus on the statistics of many-body wave functions and local energy spectra. The disorder in this chain is due to the random offset charges. This chain is one of the simplest physical systems to study many-body localization. We show that the system may exhibit three distinct regimes: insulating, characterized by the full localization of many-body wave functions, a fully delocalized (metallic) one characterized by the wave functions that take all the available phase volume, and the intermediate regime in which the volume taken by the wave function scales as a nontrivial power of the full Hilbert-space volume. In the intermediate nonergodic regime the Thouless conductance (generalized to the many-body problem) does not change as a function of the chain length indicating a failure of the conventional single-parameter scaling theory of localization transition. The local spectra in this regime display the fractal structure in the energy space which is related with the fractal structure of wave functions in the Hilbert space. A simple theory of fractality of local spectra is proposed, and a scaling relationship between fractal dimensions in the Hilbert and energy spaces is suggested and numerically tested.<br />This work was supported by ARO Grant No. W911NF- 13-1-0431 and Russian Science Foundation Grant No. 14-42- 00044. M.P. acknowledges support from Juan de la Cierva Grant No. IJCI-2015-23260, MINECO/FEDER Project No. FIS2015-70856-P, CAM PRICYT Project No. QUITEMAD+ S2013/ICE-2801, and Proyecto de la Fundacion Seneca Grant No. 19907/GERM/15.
- Subjects :
- Josephson effect
Spin glass
Condensed matter physics
Ergodicity
FOS: Physical sciences
Multifractal system
Disordered Systems and Neural Networks (cond-mat.dis-nn)
Condensed Matter - Disordered Systems and Neural Networks
01 natural sciences
010305 fluids & plasmas
Fractal
Condensed Matter::Superconductivity
Phase space
0103 physical sciences
Ergodic theory
010306 general physics
Quantum
Mathematics
Subjects
Details
- Database :
- OpenAIRE
- Journal :
- Digital.CSIC. Repositorio Institucional del CSIC, instname
- Accession number :
- edsair.doi.dedup.....1276295b01f4613ec22919cf279e3582