6,650 research outputs found
Tunneling between helical Majorana modes and helical Luttinger liquids
We propose and study the charge transport through single and double quantum
point contacts setup between helical Majorana modes and an interacting helical
Luttinger liquid. We show that the differential conductance decreases for
stronger repulsive interactions and that the point contacts become insulating
above a critical interaction strength. For a single point contact, the
differential conductance as a function of bias voltage shows a series of peaks
due to Andreev reflection of electrons in the Majorana modes. In the case of
two point contacts, interference phenomena make the structure of the individual
resonance peaks less universal and show modulations with different separation
distance between the contacts. For small separation distance the overall
features remain similar to the case of a single point contact.Comment: v.2: 14 pages, 11 figures; adding one figure, an appendix, and some
minor change
Running cosmological constant with observational tests
We investigate the running cosmological constant model with dark energy
linearly proportional to the Hubble parameter, , in which the CDM limit is recovered by taking .
We derive the linear perturbation equations of gravity under the
Friedmann-Lema\"itre-Robertson-Walker cosmology, and show the power spectra of
the CMB temperature and matter density distribution. By using the Markov chain
Monte Carlo method, we fit the model to the current observational data and find
that and for coupled to matter and radiation-matter, respectively,
along with constraints on other cosmological parameters.Comment: 12 pages, 5 figures, version accepted by PL
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