The Experts below are selected from a list of 4098 Experts worldwide ranked by ideXlab platform
Beini Gao - One of the best experts on this subject based on the ideXlab platform.
-
mott and Generalized Wigner crystal states in wse2 ws2 moire superlattices
Nature, 2020Co-Authors: Emma C. Regan, Danqing Wang, Chenhao Jin, Beini Gao, Iqbal Bakti M UtamaAbstract:Moire superlattices can be used to engineer strongly correlated electronic states in two-dimensional van der Waals heterostructures, as recently demonstrated in the correlated insulating and superconducting states observed in magic-angle twisted-bilayer graphene and ABC trilayer graphene/boron nitride moire superlattices1–4. Transition metal dichalcogenide moire heterostructures provide another model system for the study of correlated quantum phenomena5 because of their strong light–matter interactions and large spin–orbit coupling. However, experimental observation of correlated insulating states in this system is challenging with traditional transport techniques. Here we report the optical detection of strongly correlated phases in semiconducting WSe2/WS2 moire superlattices. We use a sensitive optical detection technique and reveal a Mott insulator state at one hole per superlattice site and surprising insulating phases at 1/3 and 2/3 filling of the superlattice, which we assign to Generalized Wigner crystallization on the underlying lattice6–11. Furthermore, the spin–valley optical selection rules12–14 of transition metal dichalcogenide heterostructures allow us to optically create and investigate low-energy excited spin states in the Mott insulator. We measure a very long spin relaxation lifetime of many microseconds in the Mott insulating state, orders of magnitude longer than that of charge excitations. Our studies highlight the value of using moire superlattices beyond graphene to explore correlated physics. Strongly correlated insulating Mott and Generalized Wigner phases are detected in WSe2/WS2 moire superlattices, and their electrical properties and excited spin states are studied using an optical technique.
-
Mott and Generalized Wigner crystal states in WSe2/WS2 moiré superlattices.
Nature, 2020Co-Authors: Emma C. Regan, Danqing Wang, Chenhao Jin, M. Iqbal Bakti Utama, Beini Gao, Xin Wei, Sihan Zhao, Wenyu Zhao, Zuocheng Zhang, Kentaro YumigetaAbstract:Moire superlattices can be used to engineer strongly correlated electronic states in two-dimensional van der Waals heterostructures, as recently demonstrated in the correlated insulating and superconducting states observed in magic-angle twisted-bilayer graphene and ABC trilayer graphene/boron nitride moire superlattices1–4. Transition metal dichalcogenide moire heterostructures provide another model system for the study of correlated quantum phenomena5 because of their strong light–matter interactions and large spin–orbit coupling. However, experimental observation of correlated insulating states in this system is challenging with traditional transport techniques. Here we report the optical detection of strongly correlated phases in semiconducting WSe2/WS2 moire superlattices. We use a sensitive optical detection technique and reveal a Mott insulator state at one hole per superlattice site and surprising insulating phases at 1/3 and 2/3 filling of the superlattice, which we assign to Generalized Wigner crystallization on the underlying lattice6–11. Furthermore, the spin–valley optical selection rules12–14 of transition metal dichalcogenide heterostructures allow us to optically create and investigate low-energy excited spin states in the Mott insulator. We measure a very long spin relaxation lifetime of many microseconds in the Mott insulating state, orders of magnitude longer than that of charge excitations. Our studies highlight the value of using moire superlattices beyond graphene to explore correlated physics. Strongly correlated insulating Mott and Generalized Wigner phases are detected in WSe2/WS2 moire superlattices, and their electrical properties and excited spin states are studied using an optical technique.
-
optical detection of mott and Generalized Wigner crystal states in wse2 ws2 moire superlattices
arXiv: Mesoscale and Nanoscale Physics, 2019Co-Authors: Emma C. Regan, Danqing Wang, Chenhao Jin, Beini Gao, Xin Wei, Sihan Zhao, Wenyu Zhao, Kentaro Yumigeta, Iqbal Bakti M Utama, Mark BleiAbstract:Moire superlattices are emerging as a new route for engineering strongly correlated electronic states in two-dimensional van der Waals heterostructures, as recently demonstrated in the correlated insulating and superconducting states in magic-angle twisted bilayer graphene and ABC trilayer graphene/boron nitride moire superlattices. Transition metal dichalcogenide (TMDC) moire heterostructures provide another exciting model system to explore correlated quantum phenomena, with the addition of strong light-matter interactions and large spin-orbital coupling. Here we report the optical detection of strongly correlated phases in semiconducting WSe2/WS2 moire superlattices. Our sensitive optical detection technique reveals a Mott insulator state at one hole per superlattice site ({\nu} = 1), and surprising insulating phases at fractional filling factors {\nu} = 1/3 and 2/3, which we assign to Generalized Wigner crystallization on an underlying lattice. Furthermore, the unique spin-valley optical selection rules of TMDC heterostructures allow us to optically create and investigate low-energy spin excited states in the Mott insulator. We reveal an especially slow spin relaxation lifetime of many microseconds in the Mott insulating state, orders-of-magnitude longer than that of charge excitations. Our studies highlight novel correlated physics that can emerge in moire superlattices beyond graphene.
Theodore L. Einstein - One of the best experts on this subject based on the ideXlab platform.
-
Beyond the Wigner distribution: Schrödinger equations and terrace width distributions
Physical Review E, 2005Co-Authors: Howard L. Richards, Theodore L. EinsteinAbstract:The so-called Generalized Wigner distribution has earlier been shown to be an excellent approximation for the terrace width distribution (TWD) of vicinal surfaces characterized by step-step interactions that are perpendicular to the average step direction and fall off as the inverse square of the step spacing. In this paper, we show that the Generalized Wigner distribution can be derived from a plausible, phenomenological model in which two steps interact with each other directly and with other steps through a position-dependent pressure. We also discuss generalizations to more general step-step interactions and show that the predictions are in good agreement with TWDs derived from numerical transfer-matrix calculations and Monte Carlo simulations. This phenomenological approach allows the step-step interaction to be extracted from experimental TWDs.
-
Analysis of terrace-width distributions using the Generalized Wigner surmise: Calibration using Monte Carlo and transfer-matrix calculations
Physical Review B, 2004Co-Authors: Hailu Gebremariam, Saul D. Cohen, Howard L. Richards, Theodore L. EinsteinAbstract:Measurement of terrace-width distributions (TWD's) of vicinal surfaces is used routinely to find the dimensionless strength $\~A$ of the elastic repulsion between steps. For sufficiently strong repulsions, the TWD can be described by a Gaussian about the mean step spacing, but controversy has arisen on the correct prefactor in the relation of the TWD variance to $\~A.$ Instead of the various Gaussian approximations, we have advocated for several years that the TWD be fit with the Generalized Wigner distribution, essentially a gamma distribution in the normalized squared TWs. The basis for this idea stems from a mapping of the step model to the Sutherland model of fermions in one dimension. While several applications to experiment have been successful, definitive comparison of the various approximations requires high-quality numerical data. We report transfer matrix and extensive Monte Carlo simulations of terrace-step-kink models to support our contentions. Our work includes investigation of finite-size effects and of the breakdown of the continuum picture for values of $\~A$ larger than in typical experiments.
-
Step Position Distributions and the Generalized Wigner Distribution
2003Co-Authors: Theodore L. EinsteinAbstract:Generalized Wigner Distribution exhibits the positive skew observed in TWDs from experiments and simula- tions, and it is a good fit quantitatively to TWDs pro- duced from Monte Carlo simulations of the TSK model. In this article we show that the same theory that pre- dicts the Generalized Wigner Distribution for the TWD also predicts a Gaussian-like distribution for the position of steps. For reasons that will be discussed below, the quantitative agreement between the theoretical predic- tions and measured values of the Step Position Distribu- tion (SPD) are not as good as in the case of the TWD, although the agreement is quite good considering that it is a prediction, not a fit.
-
terrace width distributions on vicinal surfaces Generalized Wigner surmise and extraction of step step repulsions
Applied Surface Science, 2001Co-Authors: Theodore L. Einstein, Saul D. Cohen, Howard L. Richards, Olivier Pierrelouis, Margret GiesenAbstract:Abstract From quantitative measurement of the equilibrium terrace-width (l) distribution (TWD) of vicinal surfaces, one can assess the strength A of elastic step–step repulsions A/l2. Generally the TWD depends only on A =A×( step stiffness )/(k B T) 2 . From ideas of fluctuation phenomena, TWDs should be describable by the “Generalized Wigner distribution” (GWD), essentially a power-law in l/〈l〉 times a “Gaussian decay” in l/〈l〉. The power-law exponent is related simply to A . Alternatively, the GWD gives the exact solution for a mean-field approximation. The GWD provides at least as good a description of TWDs as the standard fit to a Gaussian (centered at 〈l〉). It works well for weak elastic repulsion strengths A (where Gaussians fail), as illustrated explicitly for vicinal Pt(1 1 0). Application to vicinal copper surfaces confirms the viability of the GWD analysis. The GWD can be treated as a two-parameter fit by scaling l using an adjustable characteristic width. With Monte Carlo and transfer-matrix calculations, we show that for physical values of A , the GWD provides a better overall estimate than the Gaussian models. We quantify how a GWD approaches a Gaussian for large A and present a convenient, accurate expression relating the variance of the TWD to A . We describe how discreteness of terrace widths impacts the standard continuum analysis.
-
Terrace-width distributions on vicinal surfaces: Generalized Wigner surmise and extraction of step–step repulsions
Applied Surface Science, 2001Co-Authors: Theodore L. Einstein, Saul D. Cohen, Howard L. Richards, Olivier Pierre-louis, Margret GiesenAbstract:Abstract From quantitative measurement of the equilibrium terrace-width (l) distribution (TWD) of vicinal surfaces, one can assess the strength A of elastic step–step repulsions A/l2. Generally the TWD depends only on A =A×( step stiffness )/(k B T) 2 . From ideas of fluctuation phenomena, TWDs should be describable by the “Generalized Wigner distribution” (GWD), essentially a power-law in l/〈l〉 times a “Gaussian decay” in l/〈l〉. The power-law exponent is related simply to A . Alternatively, the GWD gives the exact solution for a mean-field approximation. The GWD provides at least as good a description of TWDs as the standard fit to a Gaussian (centered at 〈l〉). It works well for weak elastic repulsion strengths A (where Gaussians fail), as illustrated explicitly for vicinal Pt(1 1 0). Application to vicinal copper surfaces confirms the viability of the GWD analysis. The GWD can be treated as a two-parameter fit by scaling l using an adjustable characteristic width. With Monte Carlo and transfer-matrix calculations, we show that for physical values of A , the GWD provides a better overall estimate than the Gaussian models. We quantify how a GWD approaches a Gaussian for large A and present a convenient, accurate expression relating the variance of the TWD to A . We describe how discreteness of terrace widths impacts the standard continuum analysis.
Emma C. Regan - One of the best experts on this subject based on the ideXlab platform.
-
mott and Generalized Wigner crystal states in wse2 ws2 moire superlattices
Nature, 2020Co-Authors: Emma C. Regan, Danqing Wang, Chenhao Jin, Beini Gao, Iqbal Bakti M UtamaAbstract:Moire superlattices can be used to engineer strongly correlated electronic states in two-dimensional van der Waals heterostructures, as recently demonstrated in the correlated insulating and superconducting states observed in magic-angle twisted-bilayer graphene and ABC trilayer graphene/boron nitride moire superlattices1–4. Transition metal dichalcogenide moire heterostructures provide another model system for the study of correlated quantum phenomena5 because of their strong light–matter interactions and large spin–orbit coupling. However, experimental observation of correlated insulating states in this system is challenging with traditional transport techniques. Here we report the optical detection of strongly correlated phases in semiconducting WSe2/WS2 moire superlattices. We use a sensitive optical detection technique and reveal a Mott insulator state at one hole per superlattice site and surprising insulating phases at 1/3 and 2/3 filling of the superlattice, which we assign to Generalized Wigner crystallization on the underlying lattice6–11. Furthermore, the spin–valley optical selection rules12–14 of transition metal dichalcogenide heterostructures allow us to optically create and investigate low-energy excited spin states in the Mott insulator. We measure a very long spin relaxation lifetime of many microseconds in the Mott insulating state, orders of magnitude longer than that of charge excitations. Our studies highlight the value of using moire superlattices beyond graphene to explore correlated physics. Strongly correlated insulating Mott and Generalized Wigner phases are detected in WSe2/WS2 moire superlattices, and their electrical properties and excited spin states are studied using an optical technique.
-
Mott and Generalized Wigner crystal states in WSe2/WS2 moiré superlattices.
Nature, 2020Co-Authors: Emma C. Regan, Danqing Wang, Chenhao Jin, M. Iqbal Bakti Utama, Beini Gao, Xin Wei, Sihan Zhao, Wenyu Zhao, Zuocheng Zhang, Kentaro YumigetaAbstract:Moire superlattices can be used to engineer strongly correlated electronic states in two-dimensional van der Waals heterostructures, as recently demonstrated in the correlated insulating and superconducting states observed in magic-angle twisted-bilayer graphene and ABC trilayer graphene/boron nitride moire superlattices1–4. Transition metal dichalcogenide moire heterostructures provide another model system for the study of correlated quantum phenomena5 because of their strong light–matter interactions and large spin–orbit coupling. However, experimental observation of correlated insulating states in this system is challenging with traditional transport techniques. Here we report the optical detection of strongly correlated phases in semiconducting WSe2/WS2 moire superlattices. We use a sensitive optical detection technique and reveal a Mott insulator state at one hole per superlattice site and surprising insulating phases at 1/3 and 2/3 filling of the superlattice, which we assign to Generalized Wigner crystallization on the underlying lattice6–11. Furthermore, the spin–valley optical selection rules12–14 of transition metal dichalcogenide heterostructures allow us to optically create and investigate low-energy excited spin states in the Mott insulator. We measure a very long spin relaxation lifetime of many microseconds in the Mott insulating state, orders of magnitude longer than that of charge excitations. Our studies highlight the value of using moire superlattices beyond graphene to explore correlated physics. Strongly correlated insulating Mott and Generalized Wigner phases are detected in WSe2/WS2 moire superlattices, and their electrical properties and excited spin states are studied using an optical technique.
-
optical detection of mott and Generalized Wigner crystal states in wse2 ws2 moire superlattices
arXiv: Mesoscale and Nanoscale Physics, 2019Co-Authors: Emma C. Regan, Danqing Wang, Chenhao Jin, Beini Gao, Xin Wei, Sihan Zhao, Wenyu Zhao, Kentaro Yumigeta, Iqbal Bakti M Utama, Mark BleiAbstract:Moire superlattices are emerging as a new route for engineering strongly correlated electronic states in two-dimensional van der Waals heterostructures, as recently demonstrated in the correlated insulating and superconducting states in magic-angle twisted bilayer graphene and ABC trilayer graphene/boron nitride moire superlattices. Transition metal dichalcogenide (TMDC) moire heterostructures provide another exciting model system to explore correlated quantum phenomena, with the addition of strong light-matter interactions and large spin-orbital coupling. Here we report the optical detection of strongly correlated phases in semiconducting WSe2/WS2 moire superlattices. Our sensitive optical detection technique reveals a Mott insulator state at one hole per superlattice site ({\nu} = 1), and surprising insulating phases at fractional filling factors {\nu} = 1/3 and 2/3, which we assign to Generalized Wigner crystallization on an underlying lattice. Furthermore, the unique spin-valley optical selection rules of TMDC heterostructures allow us to optically create and investigate low-energy spin excited states in the Mott insulator. We reveal an especially slow spin relaxation lifetime of many microseconds in the Mott insulating state, orders-of-magnitude longer than that of charge excitations. Our studies highlight novel correlated physics that can emerge in moire superlattices beyond graphene.
Kenjiro Yanagi - One of the best experts on this subject based on the ideXlab platform.
-
Noncommutative versions of inequalities in quantum information theory
Analysis and Mathematical Physics, 2019Co-Authors: Ali Reza Dadkhah, Mohammad Sal Moslehian, Kenjiro YanagiAbstract:In this paper, we aim to replace in the definitions of covariance and correlation the usual trace Tr by a tracial positive map between unital $$C^*$$-algebras and to replace the functions $$x^{\alpha }$$ and $$x^{1- \alpha }$$ by functions f and g satisfying some mild conditions. These allow us to define the Generalized covariance, the Generalized variance, the Generalized correlation and the Generalized Wigner–Yanase–Dyson skew information related to the tracial positive maps and functions f and g. We persent a generalization of Heisenberg’s uncertainty relation in the noncommutative framework. We extend some inequalities and properties for the Generalized correlation and the Generalized Wigner–Yanase–Dyson skew information. Furthermore, we extend some inequalities for the Generalized skew information such as uncertainty relation and the relation between the Generalized variance and the Generalized skew information.
-
Generalized UNCERTAINTY RELATION ASSOCIATED WITH A MONOTONE OR AN ANTI-MONOTONE PAIR SKEW INFORMATION
arXiv: Functional Analysis, 2012Co-Authors: Kenjiro Yanagi, Satoshi KajiharaAbstract:We give a trace inequality related to the uncertainty relation based on the monotone or anti-monotone pair skew information, which is one of the generalizations of result given by [5]. The present paper includes the result for Generalized Wigner-Yanase-Dyson skew information as a particular case [14].
-
uncertainty relation on Generalized Wigner yanase dyson skew information
Linear Algebra and its Applications, 2010Co-Authors: Kenjiro YanagiAbstract:Abstract We give a trace inequality related to the uncertainty relation of Generalized Wigner–Yanase–Dyson skew information which is two parameter’s extension of our result in [12] .
-
Generalized Wigner yanase dyson skew information and uncertainty relation
International Symposium on Information Theory and its Applications, 2010Co-Authors: Kenjiro YanagiAbstract:We give a trace inequality related to the uncertainty relation of Generalized Wigner-Yanase-Dyson skew information which includes our result in [16].
-
Uncertainty relation on Generalized Wigner–Yanase–Dyson skew information
Linear Algebra and its Applications, 2010Co-Authors: Kenjiro YanagiAbstract:We give a trace inequality related to the uncertainty relation of Generalized Wigner–Yanase–Dyson skew information which is two parameter’s extension of our result in [12]
Wenhua Wang - One of the best experts on this subject based on the ideXlab platform.
-
Uncertainty relations with the Generalized Wigner---Yanase---Dyson skew information
Quantum Information Processing, 2018Co-Authors: Yajing Fan, Huaixin Cao, Wenhua Wang, Huixian Meng, Liang ChenAbstract:The uncertainty principle in quantum mechanics is a fundamental relation with different forms, including Heisenberg's uncertainty relation and Schrodinger's uncertainty relation. We introduce the Generalized Wigner---Yanase---Dyson correlation and the related quantities. Various properties of them are discussed. Finally, we establish several generalizations of uncertainty relation expressed in terms of the Generalized Wigner---Yanase---Dyson skew information.
-
Two Generalized Wigner–Yanase skew information and their uncertainty relations
Quantum Information Processing, 2016Co-Authors: Zhengli Chen, Li-li Liang, Wenhua WangAbstract:In this paper, we first define two Generalized Wigner–Yanase skew information \(|K_{\rho ,\alpha }|(A)\) and \(|L_{\rho ,\alpha }|(A)\) for any non-Hermitian Hilbert–Schmidt operator A and a density operator \(\rho \) on a Hilbert space H and discuss some properties of them, respectively. We also introduce two related quantities \(|S_{\rho ,\alpha }|(A)\) and \(|T_{\rho ,\alpha }|(A)\). Then, we establish two uncertainty relations in terms of \(|W_{\rho ,\alpha }|(A)\) and \(|\widetilde{W}_{\rho ,\alpha }|(A)\), which read $$\begin{aligned}&|W_{\rho ,\alpha }|(A)|W_{\rho ,\alpha }|(B)\ge \frac{1}{4}\left| \mathrm {tr}\left( \left[ \frac{\rho ^{\alpha }+\rho ^{1-\alpha }}{2} \right] ^{2}[A,B]^{0}\right) \right| ^{2},\\&\sqrt{|\widetilde{W}_{\rho ,\alpha }|(A)| \widetilde{W}_{\rho ,\alpha }|(B)}\ge \frac{1}{4} \left| \mathrm {tr}\left( \rho ^{2\alpha }[A,B]^{0}\right) \mathrm {tr} \left( \rho ^{2(1-\alpha )}[A,B]^{0}\right) \right| . \end{aligned}$$
-
two Generalized Wigner yanase skew information and their uncertainty relations
Quantum Information Processing, 2016Co-Authors: Zhengli Chen, Li-li Liang, Wenhua WangAbstract:In this paper, we first define two Generalized Wigner–Yanase skew information \(|K_{\rho ,\alpha }|(A)\) and \(|L_{\rho ,\alpha }|(A)\) for any non-Hermitian Hilbert–Schmidt operator A and a density operator \(\rho \) on a Hilbert space H and discuss some properties of them, respectively. We also introduce two related quantities \(|S_{\rho ,\alpha }|(A)\) and \(|T_{\rho ,\alpha }|(A)\). Then, we establish two uncertainty relations in terms of \(|W_{\rho ,\alpha }|(A)\) and \(|\widetilde{W}_{\rho ,\alpha }|(A)\), which read $$\begin{aligned}&|W_{\rho ,\alpha }|(A)|W_{\rho ,\alpha }|(B)\ge \frac{1}{4}\left| \mathrm {tr}\left( \left[ \frac{\rho ^{\alpha }+\rho ^{1-\alpha }}{2} \right] ^{2}[A,B]^{0}\right) \right| ^{2},\\&\sqrt{|\widetilde{W}_{\rho ,\alpha }|(A)| \widetilde{W}_{\rho ,\alpha }|(B)}\ge \frac{1}{4} \left| \mathrm {tr}\left( \rho ^{2\alpha }[A,B]^{0}\right) \mathrm {tr} \left( \rho ^{2(1-\alpha )}[A,B]^{0}\right) \right| . \end{aligned}$$