The Experts below are selected from a list of 360 Experts worldwide ranked by ideXlab platform
Yifan Jiang - One of the best experts on this subject based on the ideXlab platform.
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fermion sign free majarana quantum monte carlo studies of quantum critical phenomena of dirac Fermions in two dimensions
New Journal of Physics, 2015Co-Authors: Yifan Jiang, Hong YaoAbstract:Quantum critical phenomena may be qualitatively different when massless Dirac Fermions are present at criticality. Using our recently-discovered fermion-sign-free Majorana quantum Monte Carlo method introduced by us in (Li et al 2015 Phys. Rev. B 91 241117), we investigate the quantum critical phenomena of spinless Dirac Fermions at their charge-density-wave phase transitions on the honeycomb lattice having sites with largest L = 24. By finite-size scaling, we accurately obtain critical exponents of this so-called Gross–Neveu chiral-Ising universality class of two (two-component) Dirac Fermions in 2+1D: , , and , which are qualitatively different from the mean-field results but are reasonably close to the ones obtained from renormalization group calculations.
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fermion sign free majarana quantum monte carlo studies of quantum critical phenomena of dirac Fermions in two dimensions
arXiv: Strongly Correlated Electrons, 2014Co-Authors: Yifan Jiang, Hong YaoAbstract:Quantum critical phenomena may be qualitatively different when massless Dirac Fermions are present at criticality. Using our recently-discovered fermion-sign-free Majorana quantum Monte Carlo (MQMC) method introduced by us in Ref. [1], we investigate the quantum critical phenomena of {\it spinless} Dirac Fermions at their charge-density-wave (CDW) phase transitions on the honeycomb lattice having $N_s=2L^2$ sites with largest $L=24$. By finite-size scaling, we accurately obtain critical exponents of this so-called Gross-Neveu chiral-Ising universality class of {\it two} (two-component) Dirac Fermions in 2+1D: $\eta=0.45(2)$, $\nu=0.77(3)$, and $\beta=0.60(3)$, which are qualitatively different from the mean-field results but are reasonably close to the ones obtained from renormalization group calculations.
Biao Lian - One of the best experts on this subject based on the ideXlab platform.
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topological quantum computation based on chiral majorana Fermions
Proceedings of the National Academy of Sciences of the United States of America, 2018Co-Authors: Biao Lian, Abolhassan Vaezi, Xiaoliang Qi, Shoucheng ZhangAbstract:The chiral Majorana fermion is a massless self-conjugate fermion which can arise as the edge state of certain 2D topological matters. It has been theoretically predicted and experimentally observed in a hybrid device of a quantum anomalous Hall insulator and a conventional superconductor. Its closely related cousin, the Majorana zero mode in the bulk of the corresponding topological matter, is known to be applicable in topological quantum computations. Here we show that the propagation of chiral Majorana Fermions leads to the same unitary transformation as that in the braiding of Majorana zero modes and propose a platform to perform quantum computation with chiral Majorana Fermions. A Corbino ring junction of the hybrid device can use quantum coherent chiral Majorana Fermions to implement the Hadamard gate and the phase gate, and the junction conductance yields a natural readout for the qubit state.
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chiral majorana fermion modes in a quantum anomalous hall insulator superconductor structure
Science, 2017Co-Authors: Lei Pan, Jing Wang, Alex Stern, Edward C Burks, Xiaoyu Che, Gen Yin, Biao Lian, Quan Zhou, Eun Sang ChoiAbstract:Majorana fermion is a hypothetical particle that is its own antiparticle. We report transport measurements that suggest the existence of one-dimensional chiral Majorana fermion modes in the hybrid system of a quantum anomalous Hall insulator thin film coupled with a superconductor. As the external magnetic field is swept, half-integer quantized conductance plateaus are observed at the locations of magnetization reversals, giving a distinct signature of the Majorana fermion modes. This transport signature is reproducible over many magnetic field sweeps and appears at different temperatures. This finding may open up an avenue to control Majorana Fermions for implementing robust topological quantum computing.
Hong Yao - One of the best experts on this subject based on the ideXlab platform.
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fermion sign free majarana quantum monte carlo studies of quantum critical phenomena of dirac Fermions in two dimensions
New Journal of Physics, 2015Co-Authors: Yifan Jiang, Hong YaoAbstract:Quantum critical phenomena may be qualitatively different when massless Dirac Fermions are present at criticality. Using our recently-discovered fermion-sign-free Majorana quantum Monte Carlo method introduced by us in (Li et al 2015 Phys. Rev. B 91 241117), we investigate the quantum critical phenomena of spinless Dirac Fermions at their charge-density-wave phase transitions on the honeycomb lattice having sites with largest L = 24. By finite-size scaling, we accurately obtain critical exponents of this so-called Gross–Neveu chiral-Ising universality class of two (two-component) Dirac Fermions in 2+1D: , , and , which are qualitatively different from the mean-field results but are reasonably close to the ones obtained from renormalization group calculations.
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fermion sign free majarana quantum monte carlo studies of quantum critical phenomena of dirac Fermions in two dimensions
arXiv: Strongly Correlated Electrons, 2014Co-Authors: Yifan Jiang, Hong YaoAbstract:Quantum critical phenomena may be qualitatively different when massless Dirac Fermions are present at criticality. Using our recently-discovered fermion-sign-free Majorana quantum Monte Carlo (MQMC) method introduced by us in Ref. [1], we investigate the quantum critical phenomena of {\it spinless} Dirac Fermions at their charge-density-wave (CDW) phase transitions on the honeycomb lattice having $N_s=2L^2$ sites with largest $L=24$. By finite-size scaling, we accurately obtain critical exponents of this so-called Gross-Neveu chiral-Ising universality class of {\it two} (two-component) Dirac Fermions in 2+1D: $\eta=0.45(2)$, $\nu=0.77(3)$, and $\beta=0.60(3)$, which are qualitatively different from the mean-field results but are reasonably close to the ones obtained from renormalization group calculations.
Azadeh Maleknejad - One of the best experts on this subject based on the ideXlab platform.
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dark Fermions and spontaneous cp violation in su 2 axion inflation
Journal of High Energy Physics, 2020Co-Authors: Azadeh MaleknejadAbstract:Remarkably, if CP was spontaneously broken in the physics of inflation, Fermions would notice and remember it. Based on that, we present a new (non-thermal) mechanism for generating self-interacting dark Dirac Fermions prior to the Hot Big Bang. The non-Abelian gauge fields and axions are well-motivated matter contents for the particle physics of inflation. In this background, we analytical study Dirac fermion doublets charged under the SU(2) gauge field and use point-splitting technique to regularize the currents. We show that the non-trivial CP-violating vacuum structure of SU(2)-axion models naturally leads to an efficient mechanism for generating massive Fermions during inflation. The size of the fermionic backreaction and the density fraction of dark Fermions put upper bounds on the fermion’s mass. For a GUT scale inflation, the generated dark Fermions, only gravitationally coupled to the visible sector, can be as heavy as m ≲ 10 TeV.
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dark Fermions and spontaneous cp violation in su 2 axion inflation
arXiv: High Energy Physics - Theory, 2019Co-Authors: Azadeh MaleknejadAbstract:Remarkably, if $CP$ was spontaneously broken in the physics of inflation, Fermions would notice and remember it. Based on that, we present a new (non-thermal) mechanism for generating self-interacting dark Dirac Fermions prior to the Hot Big Bang. The non-Abelian gauge fields and axions are well-motivated matter contents for the particle physics of inflation. In this background, we analytical study Dirac fermion doublets charged under the $SU(2)$ gauge field and use point-splitting technique to regularize the currents. We show that the non-trivial $CP$-violating vacuum structure of $SU(2)$-axion models naturally leads to an efficient mechanism for generating massive Fermions during inflation. The size of the fermionic backreaction and the density fraction of dark Fermions put upper bounds on the fermion's mass. For a GUT scale inflation, the generated dark Fermions, only gravitationally coupled to the visible sector, can be as heavy as $m\lesssim 10 TeV$.
Madhab Neupane - One of the best experts on this subject based on the ideXlab platform.
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discovery of a weyl fermion semimetal and topological fermi arcs
Science, 2015Co-Authors: Ilya Belopolski, Nasser Alidoust, Madhab Neupane, Guang Bian, Chenglong Zhang, Raman Sankar, Guoqing Chang, Zhujun Yuan, Chicheng LeeAbstract:A Weyl semimetal is a new state of matter that hosts Weyl Fermions as emergent quasiparticles and admits a topological classification that protects Fermi arc surface states on the boundary of a bulk sample. This unusual electronic structure has deep analogies with particle physics and leads to unique topological properties. We report the experimental discovery of a Weyl semimetal, tantalum arsenide (TaAs). Using photoemission spectroscopy, we directly observe Fermi arcs on the surface, as well as the Weyl fermion cones and Weyl nodes in the bulk of TaAs single crystals. We find that Fermi arcs terminate on the Weyl fermion nodes, consistent with their topological character. Our work opens the field for the experimental study of Weyl Fermions in physics and materials science.
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a weyl fermion semimetal with surface fermi arcs in the transition metal monopnictide taas class
Nature Communications, 2015Co-Authors: Shinming Huang, Ilya Belopolski, Nasser Alidoust, Madhab Neupane, Guang Bian, Guoqing Chang, Chicheng Lee, B WangAbstract:Weyl Fermions are massless chiral Fermions that play an important role in quantum field theory but have never been observed as fundamental particles. A Weyl semimetal is an unusual crystal that hosts Weyl Fermions as quasiparticle excitations and features Fermi arcs on its surface. Such a semimetal not only provides a condensed matter realization of the anomalies in quantum field theories but also demonstrates the topological classification beyond the gapped topological insulators. Here, we identify a topological Weyl semimetal state in the transition metal monopnictide materials class. Our first-principles calculations on TaAs reveal its bulk Weyl fermion cones and surface Fermi arcs. Our results show that in the TaAs-type materials the Weyl semimetal state does not depend on fine-tuning of chemical composition or magnetic order, which opens the door for the experimental realization of Weyl semimetals and Fermi arc surface states in real materials. Proposals for the realization of Weyl semimetals, topologically non-trivial materials which host Weyl fermion quasiparticles, have faced demanding experimental requirements. Here, the authors predict such a state in stoichiometric TaAs, arising due to the breaking of inversion symmetry.
