期刊文献+
共找到6篇文章
< 1 >
每页显示 20 50 100
Quantum Curie-Weiss Magnet Induced by Violation of Cluster Property 被引量:1
1
作者 Tomo Munehisa 《World Journal of Condensed Matter Physics》 2020年第2期27-52,共26页
There are some concepts that are accepted in our daily life but are not trivial in physics. One of them is the cluster property that means there exist no relations between two events which are sufficiently separated. ... There are some concepts that are accepted in our daily life but are not trivial in physics. One of them is the cluster property that means there exist no relations between two events which are sufficiently separated. In the works recently published by the author, the extensive and quantitative examination has been made about the violation of cluster property in the correlation function of the spin operator for the quantum spin system. These works have shown that, when we include the symmetry breaking interaction, the effect by the violation is proportional to the inverse of the system size. Therefore this effect is tinny since the system size is quite large. In order to find the effect due to the violation even when the size is large, we propose a new system where additional spins couple with the spin system on the square lattice, where the coupling constant between these systems being assumed to be small. Applying the perturbation theory, we obtain the effective Hamiltonian for the additional system. This Hamiltonian includes Curie-Weiss model that is induced by the violation of the cluster property. Then we find that this effective Hamiltonian has the factor which is the inverse of the system size. Since Curie-Weiss model, which is known to be exactly soluble, has to contain this factor so that the thermodynamical properties are well-defined, the essential factor for the Hamiltonian is determined by the coupling and the strength of the symmetry breaking interaction. Our conclusion is, therefore, that it is possible to observe the effect by the violation of the cluster property at the inverse temperature whose order is given by these parameters. 展开更多
关键词 QUANTUM Spin SPONTANEOUS Symmetry Breaking CLUSTER PROPERTY Curie-weiss model
在线阅读 下载PDF
自组织临界点Curie-Weiss模型中的收敛速率
2
作者 刘松昊 邵启满 张梦晨 《中国科学:数学》 北大核心 2026年第1期155-186,共32页
令X1,..., Xn服从如下自组织临界点Curie-Weiss模型:dµˆ(x1,……,xn)=1 Zn exp{βn(x1+……+xn)22(x 21+……+x 2 n)}1{x 21+……+x2 n>0}∏n i=1 dρ(xi),其中βn是一个与n有关的非负参数,ρ是一个对称的具有有界支撑集的概率... 令X1,..., Xn服从如下自组织临界点Curie-Weiss模型:dµˆ(x1,……,xn)=1 Zn exp{βn(x1+……+xn)22(x 21+……+x 2 n)}1{x 21+……+x2 n>0}∏n i=1 dρ(xi),其中βn是一个与n有关的非负参数,ρ是一个对称的具有有界支撑集的概率测度, Zn是正则化常数.记Sn=∑ni=1Xi, Tn=∑ni=1X2i.本文证明了当0≤1-βn≤O(n-m), m>1/2时,统计量n1/4Sn/Tn以O(n-1/2+n1/2(1-βn))的速度收敛到一个具有特殊密度的非正态分布;当√n(1−βn)→θ,θ 是一个常数时,统计量n1/4Sn/Tn以O(n-1/2+|n1/2(1-βn)-θ|)的速度收敛到另一个具有特殊密度的非正态分布;而当O(n-m)≤1-βn,m<1/2时,(1−βn)1/2Sn/√Tn以O(n-1/2(1-βn)-1)的速度收敛到一个标准正态分布.证明是基于Stein方法以及其上的可交换对技术完成的. 展开更多
关键词 Curie-weiss模型 自组织临界点 Stein方法 自正则化 收敛速度
原文传递
研发成本粘性与技术创新绩效的关联性研究 被引量:21
3
作者 孙林杰 彭丽霞 孙万君 《科学学研究》 CSSCI CSCD 北大核心 2022年第4期695-703,共9页
技术创新绩效是衡量企业创新能力的重要指标之一,其影响因素众多,研发投入是根本。企业管理行为研究中,成本粘性研究是揭示企业“管理黑箱”的重要路径。选取2015-2019年我国工业上市企业数据为研究样本,使用WEISS模型计量企业的研发成... 技术创新绩效是衡量企业创新能力的重要指标之一,其影响因素众多,研发投入是根本。企业管理行为研究中,成本粘性研究是揭示企业“管理黑箱”的重要路径。选取2015-2019年我国工业上市企业数据为研究样本,使用WEISS模型计量企业的研发成本粘性程度,并建立研发成本粘性与技术创新绩效的关系模型,进行多元回归分析,实证检验企业研发成本粘性对技术创新绩效的影响作用。研究结果表明:首先,研发成本粘性普遍存在于我国上市企业中,且对企业技术创新绩效存在显著的正向影响作用,有助于技术创新绩效的提高,这一正向影响作用机制在非国有企业中更为显著;其次,在企业规模效应和融资约束条件下,研发成本粘性对技术创新绩效的促进作用仍显著存在但效应相对有所减弱。 展开更多
关键词 研发成本粘性 技术创新绩效 关联性 weiss模型
原文传递
信息生产能力与农业保险对农村金融市场信贷配给的影响——基于湖南岳阳市农村金融市场的实证研究 被引量:2
4
作者 刘祚祥 孙良媛 黄权国 《广东金融学院学报》 CSSCI 北大核心 2012年第4期97-107,共11页
利用修正的S-W模型论证贷款人的信息生产能力与其风险及贷款利率之间的关系;并在模型中引入农业保险,分别考察农业保险对农村信贷利率、风险及贷款人收益的影响;同时通过对岳阳市辖内六县市的调查案例和数据进行经验分析,结果表明农业... 利用修正的S-W模型论证贷款人的信息生产能力与其风险及贷款利率之间的关系;并在模型中引入农业保险,分别考察农业保险对农村信贷利率、风险及贷款人收益的影响;同时通过对岳阳市辖内六县市的调查案例和数据进行经验分析,结果表明农业保险降低了农村信贷配给,降低了信贷机构风险并增加了信贷机构收益,农业保险对农村信贷规模有显著的促进作用。 展开更多
关键词 信贷配给 农业保险 S—W模型 农村信贷市场
原文传递
上市公司并购交易中的成本粘性和价值创造 被引量:9
5
作者 杜剑 于芝麦 《现代财经(天津财经大学学报)》 CSSCI 北大核心 2018年第9期61-76,共16页
资源的稀缺性导致了市场竞争,并购重组也因此成为近年来企业减少恶性竞争的重要手段之一。以2004-2016年沪深A股上市公司中成功完成并购交易的企业为样本,采用TOBINQ值来衡量企业价值,使用处理后的Weiss模型来衡量企业的成本粘性水平。... 资源的稀缺性导致了市场竞争,并购重组也因此成为近年来企业减少恶性竞争的重要手段之一。以2004-2016年沪深A股上市公司中成功完成并购交易的企业为样本,采用TOBINQ值来衡量企业价值,使用处理后的Weiss模型来衡量企业的成本粘性水平。从成本粘性和成本反粘性两个角度出发,探究上市公司在并购交易中的成本粘性和价值提升之间的关系。实证研究发现:成本粘性对并购企业价值有显著的正向影响;成本反粘性与并购企业价值创造呈显著的负相关关系,即成本反粘性的存在不利于并购企业价值的提升;制造业并购公司的成本粘性与价值创造呈显著的正相关关系,成本反粘性与价值创造呈负相关关系。 展开更多
关键词 并购交易 成本粘性 成本反粘性 价值创造 weiss模型
原文传递
A Quantum State Scenario for Biological Self-Replication 被引量:1
6
作者 Robert Englman 《Open Journal of Biophysics》 2021年第2期159-176,共18页
With the prevalent conception of self-replication (SR, a hallmark of living systems) as a non-equilibrium process subject to thermodynamic laws, a complementary approach derives the low energy quantum states arising f... With the prevalent conception of self-replication (SR, a hallmark of living systems) as a non-equilibrium process subject to thermodynamic laws, a complementary approach derives the low energy quantum states arising from a Hamiltonian that appears to be specific for bio-systems by its containing some strongly binding terms. The bindings attract <em>properties</em> of the template (T) and the reactants to form a replicate (R). The criterion for SR that emerges from the theory is that second order (bi-linear) interaction terms between degrees of motion of T-R and the thermal bath dominate negatively over a linear self-energy term, and thereby provide a binding between the attributes of T and R. The formalism (reminiscent of the Kramers-Anderson mechanism for superexchange) is from first principles, but hinges on a drastic simplification by modelling the T, R and bath variables on interacting qubits and by congesting the attraction into a single (control) parameter. The development relies on further simplifying features, such as Random Phase Approximations and an Effective Hamiltonian formalism. The entropic balance to replication is considered and found to reside in the far surroundings. 展开更多
关键词 SELF-ORGANIZATION Living Systems Protein Conformations BIFURCATION Curie-weiss Spin model
在线阅读 下载PDF
上一页 1 下一页 到第
使用帮助 返回顶部