Direct Observation of a Majorana Quasiparticle Heat Capacity in 3He (original) (raw)
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Direct Majorana quasiparticles heat capacity observation by 3^33He Dark Matter detector
The Majorana fermion: fermion that is its own antiparticle, was predicted by Majorana in 1937. No fundamental particles are known to be Majorana fermions, although there are speculations that the neutrino is one. Many proposed theories assumes that the mysterious 'dark matter', which forms the greatest part of the universe, is composed of Majorana fermions. Even Majorana does not yet observed as a stable particle, its can be also exist as a quasiparticle in the edge of topological isolators. Here we reports the Dark Matter bolometer time constant deviation which is the result of additional Majorana heat capacity.
Observation of Majorana Quasiparticles’ Edge States in Superfluid 3He
Applied Magnetic Resonance, 2014
We suggest in this article the nuclear magnetic resonance (NMR) method of observation and investigations of Majorana fermions at the edge of Topological Insulator, superfluid 3 He-B. The Majorana fermions form the remarkable quantum state of condensed matter where particle-like and antiparticle (holelike) excitations are indistinguishable. They have been observed recently by deviation of the temperature dependence of the superfluid 3 He-B heat capacity from the well-known exponential law for Bogoliubov quasiparticles at the world limit of ultra-low temperatures. The experimental data are well described by adding the heat capacity of Majorana quasiparticles' edge states with zero energy gap. We report here the results of the similar experiments with extended temperature range down to 125 lK. The possible way to detect these states by means of NMR is also discussed.
Majorana Fermions: Direct Observation in 3He
2015
In this letter we report the first direct observation of gap-less Majorana QPs which appear as Andreev bound states on the surface of superfluid 3^33He-B. We made the precise measurements of superfluid 3He-B heat capacity at the limit of extremely low temperatures. We have separated the heat capacity of bulk Bogolyubov QPs and the surface Majorana QPs by its different temperature dependence. We have found that at 0.11 mK the Majorana fermions constitute half of the bolometer heat capacity under the conditions of our experiments.
Majorana Bound State in Rotating Superfluid He3-A between Parallel Plates
Physical Review Letters, 2008
A concrete and experimentally feasible example for testing the putative Majorana zero energy state bound in a vortex is theoretically proposed for a parallel plate geometry of superfluid 3 He-A phase. We examine the experimental setup in connection with ongoing rotating cryostat experiments. The theoretical analysis is based on the well-established Ginzburg-Landau functional, supplemented by microscopic calculations of the Bogoliubov-de Gennes equation, both of which allow the precise location of the parameter regions of the Majorana state to be found in realistic situations. PACS numbers: 67.30.he, 67.30.ht, 71.10.Pm Much attention has been focused on Majorana zeroenergy states in various research fields[1], for example, leptogenesis in cosmology in connection with the matterantimatter imbalance problem[2], the fractional quantum Hall state, chiral superconductors, and p-wave superfluids in neutral atomic gases. Of particular interest is the possible application to quantum computing, based on the fact that a pair of Majorana states is intrinsically entangled and topologically protected from external disturbance. For chiral superconductors and p-wave superfluids, the key is finding the Majorana zero energy state bound in a vortex. Its existence is guaranteed by the index theorem[1], implying in this context that in spinless chiral p-wave pairing p x ± ip y of two dimension (2D), an odd winding number vortex always possesses a Majorana state at exactly zero energy relative to the Fermi level. This state is localized at the core[3].
2016
We present new limits on exotic keV-scale physics based on 478 kg d of MAJORANA DEMONSTRATOR commissioning data. Constraints at the 90% confidence level are derived on bosonic dark matter (DM) and solar axion couplings, Pauli exclusion principle violating (PEPV) decay, and electron decay using monoenergetic peak signal limits above our background. Our most stringent DM constraints are set for 11.8 keV mass particles, limiting g Ae < 4.5 × 10 −13 for pseudoscalars and ðα 0 =αÞ < 9.7 × 10 −28 for vectors. We also report a 14.4 keV solar axion coupling limit of g eff AN × g Ae < 3.8 × 10 −17 , a 1 2 β 2 < 8.5 × 10 −48 limit on the strength of PEPV electron transitions, and a lower limit on the electron lifetime of τ e > 1.2 × 10 24 yr for e − → invisible.
Majorana Fermions in Condensed Matter Physics: The 1D Nanowire Case
2018
Majorana fermions are fermions that are their own antiparticles. Although they remain elusive as elementary particles (how they were originally proposed), they have rapidly gained interest in condensed matter physics as emergent quasiparticles in certain systems like topological superconductors. In this article, we briefly review the necessary theory and discuss the “recipe” to create Majorana particles. We then consider existing experimental realisations and their methodologies.
Probing Majorana fermions in spin-orbit-coupled atomic Fermi gases
Physical Review A, 2012
We examine theoretically the visualization of Majorana fermions in a two-dimensional trapped ultracold atomic Fermi gas with spin-orbit coupling. By increasing an external Zeeman field, the trapped gas transits from non-topological to topological superfluid, via a mixed phase in which both types of superfluids coexist. We show that the zero-energy Majorana fermion, supported by the topological superfluid and localized at the vortex core, is clearly visible through (i) the core density and (ii) the local density of states, which are readily measurable in experiment. We present a realistic estimate on experimental parameters for ultracold 40 K atoms.
Half quantum vortices and Majorana fermions in triplet superconductors
Half quantum vortices (HQVs) in superfluid 3He − A have been speculated since 1976. Two years ago, Yamashita et al[1] reported a very unusual NMR satellite in the rotating superfluid 3He − A in a parallel plate geometry. Recently this satellite has been interpreted in terms of HQVs[2]. Also, the strong flux pinnings in the triplet superconductors UPt3, Sr2RuO4 and U1−xThxBe13 have been discovered by Mota and her colleagues[3][4] which are interpreted in terms of HQVs[5][6][7]. We shall first review the bound state spectra around a single vortex in unconventional superconductors, which provides the necessary background. In particular, we find the zero modes of the Majorana fermions in some of triplet superconductors UPt3, Sr2RuO4 and CePt3Sn. Armed with these results we analyze the microscopic aspects of HQVs in UPt3 and Sr2RuO4. We compute the quasiparticle density of states and the local magnetic field around HQVs, which should be accessible to scanning tunneling microscopy (STM), micro-magnetometry and neutron scattering below 300 mK.
Physical Review A, 2013
We discuss the thermodynamic signatures for the topological phase transitions into Majorana and Weyl superfluid phases in ultracold Fermi gases in two and three dimensions in the presence of Rashba spin-orbit coupling and a Zeeman field. We analyze the thermodynamic properties exhibiting the distinct nature of the topological phase transitions linked with the Majorana fermions (2D Fermi gas) and Weyl fermions (3D Fermi gas) which can be observed experimentally, including pressure, chemical potential, isothermal compressibility, entropy, and specific heat, as a function of the interaction and the Zeeman field at both zero and finite temperatures. We conclude that among the various thermodynamic quantities, the isothermal compressibility and the chemical potential as a function of the artificial Zeeman field have the strongest signatures of the topological transitions in both two and three dimensions.
Majorana Edge Modes of Superfluid 3 He A-Phase in a Slab
Journal of the Physical Society of Japan, 2010
Motivated by a recent experiment on the superfluid 3 He A-phase with a chiral p-wave pairing confined in a thin slab, we propose designing a concrete experimental setup for observing the Majorana edge modes that appear around the circumference edge region. We solve the quasiclassical Eilenberger equation, which is quantitatively reliable, to evaluate several observables. To derive the property inherent to the Majorana edge state, the full quantum mechanical Bogoliubov-de Gennes equation is solved in this setting. On the basis of the results obtained, we perform decisive experiments to check the Majorana nature.