# Superconductivity

## New submissions

[ total of 8 entries: 1-8 ]
[ showing up to 1000 entries per page: fewer | more ]

### New submissions for Wed, 8 Feb 23


Title: Hamiltonian extrema of an arbitrary flux-biased Josephson circuit
Subjects: Superconductivity (cond-mat.supr-con)

Flux-biased loops including one or more Josephson junctions are ubiquitous elements in quantum information experiments based on superconducting circuits. These quantum circuits can be tuned to implement a variety of Hamiltonians, with applications ranging from decoherence-protected qubits to quantum limited converters and amplifiers. The extrema of the Hamiltonian of these circuits are of special interest because they govern their low-energy dynamics. However, the theory of superconducting quantum circuits lacks so far a systematic method to compute the series expansion of the Hamiltonian around these extrema for an arbitrary non-linear superconducting circuit. We present such method, which can aid the synthesis of new functionalities in quantum devices.


Title: Temperature dependence of the lower critical field of the noncentrosymmetric superconductor $α$-BiPd
Subjects: Superconductivity (cond-mat.supr-con)

Temperature variation of the lower critical field in the noncentrosymmetric superconductor $\alpha$-BiPd was probed by local magnetization measurements using Hall micromagnetometry, performed down to 0.3 K in a magnetic field applied along the crystallographic $b$ axis. Below a critical temperature $T_c \simeq$ 3.8 K, a conventional $H_{c1}(T)$ dependence was found, typical for a single-band $s$-wave BCS superconductor. The obtained data imply an absence of spin-triplet component in the superconducting wavefunction and marginal multiband effects in this material, which contradicts some literature reports.


Title: Single crystal growth of and hyperfine couplings in the spin-triplet superconductor K$_2$Cr$_3$As$_3$
Authors: Seigo Ogawa (1), Tomoki Miyoshi (1), Kazuaki Matano (1), Yoshihiko Inada (2), Guo-qing Zheng (1) ((1) Department of Physics, Okayama University (2) Facullty of Education, Okayama University)
Subjects: Superconductivity (cond-mat.supr-con)

We report single crystal growth of strongly-correlated compound K$_2$Cr$_3$As$_3$ with superconducting temperature $T_{\textrm c}$=6.2 K, and the measurements of magnetic susceptibility $\chi$ above $T_{\textrm c}$. We determined the hyperfine coupling constants directly from the relation between the Knight shift ($K$) and susceptibility ($K$-$\chi$ plot) and obtained the orbital contribution $K_{\textrm{orb}}$. Our results of $K_{\textrm{orb}}$ is in fairly good agreement with the previous estimate using a novel method, and reinforce the conclusion that K$_2$Cr$_3$As$_3$ is a spin-triplet superconductor.

### Cross-lists for Wed, 8 Feb 23

  arXiv:2302.03381 (cross-list from cond-mat.str-el) [pdf, other]
Title: Influence of $f$ Electrons on the Electronic Band Structure of Rare-Earth Nickelates
Subjects: Strongly Correlated Electrons (cond-mat.str-el); Materials Science (cond-mat.mtrl-sci); Superconductivity (cond-mat.supr-con)

Recently, superconductivity was discovered in the infinite layer of hole-doped nickelates NdNiO$_{2}$. Contrary to this, superconductivity in LaNiO$_{2}$ is still under debate. This indicates the crucial role played by the $f$ electrons on the electronic structure and the pairing mechanism of infinite-layer nickelates. Here we discuss the role of the electron correlations on the $f$ electron states and their influence on the electronic structure. We show that the lattice parameters are in good agreement with the experimental values, independent of the chosen parameters within the DFT+$U$ approach. Increasing Coulomb interaction $U$ tends to shift the $f$ states away from the Fermi level. Surprisingly, independently of the position of $f$ states with respect to the Fermi energy, these states play an important role in the electronic band structure, which can be reflected in the modification of the NdNiO$_{2}$ effective models.

  arXiv:2302.03446 (cross-list from cond-mat.quant-gas) [pdf, ps, other]
Title: Brueckner $G$-matrix approach to two-dimensional Fermi gases with the finite-range attractive interaction
Subjects: Quantum Gases (cond-mat.quant-gas); Strongly Correlated Electrons (cond-mat.str-el); Superconductivity (cond-mat.supr-con)

Two-dimensional spin-1/2 fermions with the finite-range interaction are theoretically studied. Characterizing the attractive interaction in terms of the scattering length and the effective range, we discuss the finite-range effects on the ground-state properties in this system. The Brueckner $G$-matrix approach is employed to analyze the finite-range effects on an attractive Fermi-polaron energy and the equation of state throughout the BEC-BCS crossover in two dimensions, which can be realized in the population-imbalanced and -balanced cases between two components, respectively. The analytical formulae for these ground states obtained in this study would be useful for understanding many-body phenomena with finite-range interactions in low-dimensional systems.

### Replacements for Wed, 8 Feb 23

  arXiv:2206.07014 (replaced) [pdf, other]
Title: Nonequilibrium Josephson diode effect in periodically driven SNS junctions
Authors: Abhiram Soori
Comments: 8 pages, 7 captioned figures
Subjects: Superconductivity (cond-mat.supr-con); Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
  arXiv:2212.12520 (replaced) [pdf, other]
Title: Observation of suppressed viscosity in the normal state of $^3$He due to superfluid fluctuations
{"ft_lang_label":"__label__en","ft_lang_prob":0.80797297,"math_prob":0.93010485,"size":873,"snap":"2022-40-2023-06","text_gpt3_token_len":330,"char_repetition_ratio":0.18411967,"word_repetition_ratio":0.17391305,"special_character_ratio":0.42611682,"punctuation_ratio":0.2356021,"nsfw_num_words":0,"has_unicode_error":false,"math_prob_llama3":0.975752,"pos_list":[0],"im_url_duplicate_count":[null],"WARC_HEADER":"{\"WARC-Type\":\"response\",\"WARC-Date\":\"2023-02-08T23:35:24Z\",\"WARC-Record-ID\":\"<urn:uuid:61a896d3-8d4b-4cbc-92d2-53489de2cac7>\",\"Content-Length\":\"24698\",\"Content-Type\":\"application/http; msgtype=response\",\"WARC-Warcinfo-ID\":\"<urn:uuid:1b214d42-938e-4b81-b293-1c87f3ff4136>\",\"WARC-Concurrent-To\":\"<urn:uuid:4b0fbac8-1ae5-417f-8318-91abf9da6e9c>\",\"WARC-IP-Address\":\"128.84.21.199\",\"WARC-Target-URI\":\"https://aps.arxiv.org/list/cond-mat.supr-con/new?skip=0&show=1000\",\"WARC-Payload-Digest\":\"sha1:XTX4NUOBAZ2ZQNI6RKBM44F7C7HCQEQE\",\"WARC-Block-Digest\":\"sha1:VM6XXDU6L6XM57OYZ3KF73SIEOEBLPJ2\",\"WARC-Identified-Payload-Type\":\"application/xhtml+xml\",\"warc_filename\":\"/cc_download/warc_2023/CC-MAIN-2023-06/CC-MAIN-2023-06_segments_1674764500983.76_warc_CC-MAIN-20230208222635-20230209012635-00249.warc.gz\"}"}