This study investigates the physical properties of the rare earth XFes(X=Sm,Dy,or Nd)materials.Our analysis encompasses these compounds'structural,electronic,thermodynamic,and optical characteristics using density...This study investigates the physical properties of the rare earth XFes(X=Sm,Dy,or Nd)materials.Our analysis encompasses these compounds'structural,electronic,thermodynamic,and optical characteristics using density functional theory(DFT)as implemented in the Wien2k software package.The GGA+SOC+U method was employed to determine the exchange-correlation potential.Our results show that the XFes materials exhibit metallic behavior and exhibit ferromagnetic(FM)phases.Notably,our optical analysis reveals a strong absorption response in the UV region,with characteristic absorption curves and peak intensities varying across the different materials.We also investigated the thermodynamic properties of the materials,finding that the entropy increases exponentially with temperature as the materials transition from a ground state to a more disordered and amorphous state.Our thermodynamic results show that the Debye temperature decreases for all three materials,with DyFes exhibiting the highest Debye temperature at 0 K(307 K),followed by NdFes(298 K),and then SmFes(288 K).This indicates that each material has a unique thermal energy barrier to overcome before vibrations occur.As the temperature increases,the Debye temperature decreases,reflecting a decrease in the thermal energy required to induce vibrations.The differences in Debye temperature values between the three materials may suggest differences in their lattice structures or phonon properties,highlighting the importance of understanding these thermal properties for developing new materials and technologies.展开更多
Quantum correlations that surpass entanglement are of great importance in the realms of quantum information processing and quantum computation.Essentially,for quantum systems prepared in pure states,it is difficult to...Quantum correlations that surpass entanglement are of great importance in the realms of quantum information processing and quantum computation.Essentially,for quantum systems prepared in pure states,it is difficult to differentiate between quantum entanglement and quantum correlation.Nonetheless,this indistinguishability is no longer holds for mixed states.To contribute to a better understanding of this differentiation,we have explored a simple model for both generating and measuring these quantum correlations.Our study concerns two macroscopic mechanical resonators placed in separate Fabry–Pérot cavities,coupled through the photon hopping process.this system offers a comprehensively way to investigate and quantify quantum correlations beyond entanglement between these mechanical modes.The key ingredient in analyzing quantum correlation in this system is the global covariance matrix.It forms the basis for computing two essential metrics:the logarithmic negativity(E_(N)^(m))and the Gaussian interferometric power(P_(G)^(m)).These metrics provide the tools to measure the degree of quantum entanglement and quantum correlations,respectively.Our study reveals that the Gaussian interferometric power(P_(G)^(m))proves to be a more suitable metric for characterizing quantum correlations among the mechanical modes in an optomechanical quantum system,particularly in scenarios featuring resilient photon hopping.展开更多
In Li and Luo(2007 Phys.Rev.A 76032327),the inequality(1/2)T≥Q was identified as a fundamental postulate for a consistent theory of quantum versus classical correlations for arbitrary measures of total T and quantum ...In Li and Luo(2007 Phys.Rev.A 76032327),the inequality(1/2)T≥Q was identified as a fundamental postulate for a consistent theory of quantum versus classical correlations for arbitrary measures of total T and quantum Q correlations in bipartite quantum states.Besides,Hayden et al(2006 Commun.Math.Phys.26595)have conjectured that,in some conditions within systems endowed with infinite-dimensional Hilbert spaces,quantum correlations may dominate not only half of total correlations but total correlations itself.Here,in a two-mode Gaussian state,quantifying T and Q respectively by the quantum mutual information I~G and the entanglement of formation(EoF)ε_(F)^(G),we verify thatε_(F)^(G),is always less than(1/2)I_(R)^(G( when I~G andε_(F)^(G) are defined via the Rényi-2 entropy.While via the von Neumann entropy,ε_(F,V)^(G),may even dominate I_(V)^(G) itself,which partly consolidates the Hayden conjecture,and partly,provides strong evidence hinting that the origin of this counterintuitive behavior should intrinsically be related to the von Neumann entropy by which the EoFε_(F,V)^(G),is defined,rather than related to the conceptual definition of the EoFε_(F).The obtained results show that—in the special case of mixed two-mode Gaussian states—quantum entanglement can be faithfully quantified by the Gaussian Rényi-2 EoFε_(F,R)^(G),.展开更多
The recent observation of higher quark combinations, tetraquarks and pentaquarks, is a strong indication of more exotic hadrons. Using Z_2 and Z_3 symmetries and standard model data, a general quark combination produc...The recent observation of higher quark combinations, tetraquarks and pentaquarks, is a strong indication of more exotic hadrons. Using Z_2 and Z_3 symmetries and standard model data, a general quark combination producing new hadronic states is proposed in terms of polygon geometries according to the Dynkin diagrams of ?_n affine Lie algebras. It has been shown that Z_(2,3) invariance is crucial in the determination of the mesonic or the baryonic nature of these states. The hexagonal geometry is considered in some details producing both mesonic and baryonic states. A general class of this family is also presented.展开更多
We investigate the generation of quantum correlations between mechanical modes and optical modes in an optomechanical system,using the rotating wave approximation.The system is composed of two Fabry-Pérot cavitie...We investigate the generation of quantum correlations between mechanical modes and optical modes in an optomechanical system,using the rotating wave approximation.The system is composed of two Fabry-Pérot cavities separated in space;each of the two cavities has a movable end-mirror.Our aim is the evaluation of entanglement between mechanical modes and optical modes,generated by correlations transfer from the squeezed light to the system,using Gaussian intrinsic entanglement as a witness of entanglement in continuous variables Gaussian states,and the quantification of the degree of mixedness of the Gaussian states using the purity.Then,we quantify nonclassical correlations between mechanical modes and optical modes even beyond entanglement by considering Gaussian geometric discord via the Hellinger distance.Indeed,entanglement,mixdness,and quantum discord are analyzed as a function of the parameters characterizing the system(thermal bath temperature,squeezing parameter,and optomechanical cooperativity).We find that,under thermal effect,when entanglement vanishes,purity and quantum discord remain nonzero.Remarkably,the Gaussian Hellinger discord is more robust than entanglement.The effects of the other parameters are discussed in detail.展开更多
Rutile germanium oxide(rutile GeO_(2)),a semiconductor,can act as a half-metallic compound and is a promising material for spintronic and optoelectronic applications.Calculations were performed using the Korringa–Koh...Rutile germanium oxide(rutile GeO_(2)),a semiconductor,can act as a half-metallic compound and is a promising material for spintronic and optoelectronic applications.Calculations were performed using the Korringa–Kohn–Rostoker(KKR)approach and the coherent potential approximation(CPA),which were further combined with two approximations,the local density approximation(LDA)and the self-interaction corrected LDA approximation(LDA-SIC),to study the electronic structure of bulk rutile GeO_(2) doped and co-doped with three transition-metal impurities:Fe,Co,and Ni.The doping value was set to 10%,while the co-doping level was set to 5%for each impurity.The main findings of this work are:(1)a direct ultrawide bandgap of4.80 eV is observed and the rutile GeO_(2) exhibits an N-type semiconducting property.(2)Doped and co-doped GeO_(2) acquire a magnetic behavior and exhibit half-metallicity.(3)The mechanism responsible for these properties is also studied.(4)The critical temperature can reach 334 K when GeO_(2) is doped with Fe,while it rises to 398 K when it is co-doped with Fe and Co.(5)The spin polarization can be improved by co-doping.It can be inferred that rutile GeO_(2) doped or codoped with(Co,Fe)transition metals can be considered to be potential candidates for spintronic and optoelectronic applications.展开更多
文摘This study investigates the physical properties of the rare earth XFes(X=Sm,Dy,or Nd)materials.Our analysis encompasses these compounds'structural,electronic,thermodynamic,and optical characteristics using density functional theory(DFT)as implemented in the Wien2k software package.The GGA+SOC+U method was employed to determine the exchange-correlation potential.Our results show that the XFes materials exhibit metallic behavior and exhibit ferromagnetic(FM)phases.Notably,our optical analysis reveals a strong absorption response in the UV region,with characteristic absorption curves and peak intensities varying across the different materials.We also investigated the thermodynamic properties of the materials,finding that the entropy increases exponentially with temperature as the materials transition from a ground state to a more disordered and amorphous state.Our thermodynamic results show that the Debye temperature decreases for all three materials,with DyFes exhibiting the highest Debye temperature at 0 K(307 K),followed by NdFes(298 K),and then SmFes(288 K).This indicates that each material has a unique thermal energy barrier to overcome before vibrations occur.As the temperature increases,the Debye temperature decreases,reflecting a decrease in the thermal energy required to induce vibrations.The differences in Debye temperature values between the three materials may suggest differences in their lattice structures or phonon properties,highlighting the importance of understanding these thermal properties for developing new materials and technologies.
文摘Quantum correlations that surpass entanglement are of great importance in the realms of quantum information processing and quantum computation.Essentially,for quantum systems prepared in pure states,it is difficult to differentiate between quantum entanglement and quantum correlation.Nonetheless,this indistinguishability is no longer holds for mixed states.To contribute to a better understanding of this differentiation,we have explored a simple model for both generating and measuring these quantum correlations.Our study concerns two macroscopic mechanical resonators placed in separate Fabry–Pérot cavities,coupled through the photon hopping process.this system offers a comprehensively way to investigate and quantify quantum correlations beyond entanglement between these mechanical modes.The key ingredient in analyzing quantum correlation in this system is the global covariance matrix.It forms the basis for computing two essential metrics:the logarithmic negativity(E_(N)^(m))and the Gaussian interferometric power(P_(G)^(m)).These metrics provide the tools to measure the degree of quantum entanglement and quantum correlations,respectively.Our study reveals that the Gaussian interferometric power(P_(G)^(m))proves to be a more suitable metric for characterizing quantum correlations among the mechanical modes in an optomechanical quantum system,particularly in scenarios featuring resilient photon hopping.
基金I am particularly indebted to an anonymous referee for constructive critiques and insightful comments.
文摘In Li and Luo(2007 Phys.Rev.A 76032327),the inequality(1/2)T≥Q was identified as a fundamental postulate for a consistent theory of quantum versus classical correlations for arbitrary measures of total T and quantum Q correlations in bipartite quantum states.Besides,Hayden et al(2006 Commun.Math.Phys.26595)have conjectured that,in some conditions within systems endowed with infinite-dimensional Hilbert spaces,quantum correlations may dominate not only half of total correlations but total correlations itself.Here,in a two-mode Gaussian state,quantifying T and Q respectively by the quantum mutual information I~G and the entanglement of formation(EoF)ε_(F)^(G),we verify thatε_(F)^(G),is always less than(1/2)I_(R)^(G( when I~G andε_(F)^(G) are defined via the Rényi-2 entropy.While via the von Neumann entropy,ε_(F,V)^(G),may even dominate I_(V)^(G) itself,which partly consolidates the Hayden conjecture,and partly,provides strong evidence hinting that the origin of this counterintuitive behavior should intrinsically be related to the von Neumann entropy by which the EoFε_(F,V)^(G),is defined,rather than related to the conceptual definition of the EoFε_(F).The obtained results show that—in the special case of mixed two-mode Gaussian states—quantum entanglement can be faithfully quantified by the Gaussian Rényi-2 EoFε_(F,R)^(G),.
文摘The recent observation of higher quark combinations, tetraquarks and pentaquarks, is a strong indication of more exotic hadrons. Using Z_2 and Z_3 symmetries and standard model data, a general quark combination producing new hadronic states is proposed in terms of polygon geometries according to the Dynkin diagrams of ?_n affine Lie algebras. It has been shown that Z_(2,3) invariance is crucial in the determination of the mesonic or the baryonic nature of these states. The hexagonal geometry is considered in some details producing both mesonic and baryonic states. A general class of this family is also presented.
文摘We investigate the generation of quantum correlations between mechanical modes and optical modes in an optomechanical system,using the rotating wave approximation.The system is composed of two Fabry-Pérot cavities separated in space;each of the two cavities has a movable end-mirror.Our aim is the evaluation of entanglement between mechanical modes and optical modes,generated by correlations transfer from the squeezed light to the system,using Gaussian intrinsic entanglement as a witness of entanglement in continuous variables Gaussian states,and the quantification of the degree of mixedness of the Gaussian states using the purity.Then,we quantify nonclassical correlations between mechanical modes and optical modes even beyond entanglement by considering Gaussian geometric discord via the Hellinger distance.Indeed,entanglement,mixdness,and quantum discord are analyzed as a function of the parameters characterizing the system(thermal bath temperature,squeezing parameter,and optomechanical cooperativity).We find that,under thermal effect,when entanglement vanishes,purity and quantum discord remain nonzero.Remarkably,the Gaussian Hellinger discord is more robust than entanglement.The effects of the other parameters are discussed in detail.
文摘Rutile germanium oxide(rutile GeO_(2)),a semiconductor,can act as a half-metallic compound and is a promising material for spintronic and optoelectronic applications.Calculations were performed using the Korringa–Kohn–Rostoker(KKR)approach and the coherent potential approximation(CPA),which were further combined with two approximations,the local density approximation(LDA)and the self-interaction corrected LDA approximation(LDA-SIC),to study the electronic structure of bulk rutile GeO_(2) doped and co-doped with three transition-metal impurities:Fe,Co,and Ni.The doping value was set to 10%,while the co-doping level was set to 5%for each impurity.The main findings of this work are:(1)a direct ultrawide bandgap of4.80 eV is observed and the rutile GeO_(2) exhibits an N-type semiconducting property.(2)Doped and co-doped GeO_(2) acquire a magnetic behavior and exhibit half-metallicity.(3)The mechanism responsible for these properties is also studied.(4)The critical temperature can reach 334 K when GeO_(2) is doped with Fe,while it rises to 398 K when it is co-doped with Fe and Co.(5)The spin polarization can be improved by co-doping.It can be inferred that rutile GeO_(2) doped or codoped with(Co,Fe)transition metals can be considered to be potential candidates for spintronic and optoelectronic applications.
