共查询到18条相似文献,搜索用时 734 毫秒
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通过分析系统的杂质位与其余部分间的纠缠N1-A以及单个正常位与其余部分间的纠缠NL-A研究了匀强磁场作用下含杂质Heisenberg XX链的纠缠特性.研究表明三量子位时纠缠存在的临界温度依赖于杂质参数J1和匀强磁场B.研究发现,当量子位L为奇数时,纠缠N1-A随量子位的增加而增大,而L为偶数时则相反,并且量子位L为偶数时的纠缠大于量子位L为奇数时的纠缠;对NL-A,量子位L为奇数时,纠缠随杂质参数J1的变化与L=3类似,而L为偶数时纠缠随杂质参数|J1|的增加而增加. 相似文献
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多模偶相干态光场中的N次方Y压缩与N次方H压缩特性研究 总被引:62,自引:39,他引:23
本文根据新近建立的多模辐射场的广义非线性等阶高阶压缩理论,对多模偶相干态光场冲|ψ,e〉q中的N次方Y压缩、N次方H压缩、N-Y最小测不准态以及N-H最小测不准态等进行了详细研究。结果表明:1)当N为偶数时,态|ψ,e〉q恒处于N-Y最小测不准态;当N为奇数时,态|ψ,e〉q在一定条件下存在着周期性变化的、任意阶的N次方Y压缩效应,2)当q·N为偶数时,态|ψ,e〉q恒处于N-H最小测不准态。当q·N为奇数时,在另外的条件下,态|ψ,e〉q存在着周期性变化的、任意阶的N次方H压缩效应。3)N次方Y压缩效应与N次方H压缩效应两者的压缩程度和深度均与几率幅yq(e)、压缩参数Rj、各模的初始相位ψj(或者初始相位和∑j=1qψj)、压缩阶数N及腔模总数q等非线性相关,后者与上述诸参量的非线性关联程度要比前者的更强。 相似文献
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多模奇相干态光场中的N-Y最小测不准态与N-H最小测不准态 总被引:56,自引:33,他引:23
本文根据新近建立的多模辐射场的广义非线性等阶高阶压缩理论,对多模奇相干态光场|Ψ,o〉q中的N次方Y压缩、N次方H压缩、N-Y最小测不准态以及N-H最小测不准态等进行了详细研究.结果表明:1)当压缩阶数N为偶数时,多模奇相干态|Ψ,o〉q总是恒处于N-Y最小测不准态;当N为奇数时,态|Ψ,o〉q既不处于N-Y最小测不准态,也不呈现N次方Y压缩效应.2)当q & #183;N为偶数时,多模奇相干态|Ψ,o〉q总是恒处于N-H最小测不准态;当q & #183;N为奇数时,态|Ψ,o〉q既不处于N-H最小测不准态,也不呈现N次方H压缩效应.3)多模奇相干态|Ψ,o〉q恒处于N-Y最小测不准态与恒处于N-H最小测不准态的条件明显不同,两者存在着严格的区别. 相似文献
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第Ⅰ类两态叠加多模叠加态光场的非线性高阶压缩特性研究 总被引:87,自引:30,他引:57
本文在文献20的基础上进一步提出了多模辐射场的N-Y最小测不准态、N-H最小测不准态、N-Y压缩最小测不准态以及N-H压缩最小测不准态等的定义.构造了由多模(q模)相干态|{Zj}>q及其相反态|{-Zj}>q的线性叠加所组成的第Ⅰ类两态叠加多模叠加态光场|ψ1(2)>q,利用文献20新近提出的有关多模辐射场的两种非线性高阶压缩的定义,首次对态|ψ1(2)>q的N次方Y压缩及N次方H压缩效应进行了详细研究.结果表明,1)当N为偶数时,态|ψ1(2)>q恒处于N-Y最小测不准态;当N为奇数时,态|ψ1(2)>q在一定条件下可呈现出周期性变化的、任意阶的N次方Y压缩效应.2)当q·N为偶数时,态|ψ1(2)>q恒处于N-H最小测不准态;当q·N为奇数时,在另外的条件下,态|ψ1(2)>q则可呈现出周期性变化的、任意阶的N次方H压缩效应.3)N次方Y压缩及N次方H压缩效应的压缩深度与腔模总数q、压缩参数Rj以及压缩阶数N等非线性相关,后者与上述参量的非线性关联程度要比前者的更强. 相似文献
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一种新型的多模虚奇相干态光场的两种等阶最小测不准态——等阶N-Y与等阶N-H最小测不准态 总被引:32,自引:20,他引:12
本文利用新近建立的多模压缩态理论,详细研究了一种新型的多模虚奇相干态光场|Ψi,o(2)〉q的广义非线性等阶高阶压缩特性.结果发现:1)当压缩阶数 N为偶数时,多模虚奇相干态 |Ψi,o(2)〉q总是恒处于等阶 N-Y最小测不准态;而当 N为奇数时,态 |Ψi,o(2)〉q既不处于等阶 N-Y最小测不准态,也不呈现等阶 N次方 Y压缩效应.2)当腔模总数 q与压缩阶数 N这两者之积 q&183;N为偶数时,多模虚奇相干态 |Ψi,o(2)〉q 始终恒处于等阶 N-H最小测不准态;而当q&183;N为奇数时,态 |Ψi,o(2)〉q 既不处于等阶 N-H最小测不准态,也不呈现等阶 N次方 H压缩效应.3)上述的等阶 N-Y最小测不准态与等阶 N-H最小测不准态属于两种截然不同的等阶最小测不准态,两者无论在定义上、性质上、条件上还是在产生机制上都存在着严格的本质区别.4)多模虚奇相干态光场 |Ψi,o(2)〉q与已报道的多模奇相干态光场 |Ψ,o〉q和多模复共轭奇相干态光场 |Ψ*,o(2)〉q等虽是三种不同的量子光场态,但却具有完全相同的量子统计性质;即在相同条件下它们都恒处于上述的两种等阶最小测不准态,但始终不呈现等阶 N次方 Y压缩与等阶 N次方 H压缩效应. 相似文献
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两种特殊四态叠加多模叠加态光场的等N次幂H压缩 总被引:3,自引:0,他引:3
根据线性叠加原理,用多模相干态|{Zj*}〉q,|{-Zj*}〉q及其复共轭|{Zj*}〉q和|{-Zj*}〉q组成了两种四态叠加多模叠加态光场|Ψoe(4)Ⅵ〉q和|Ψ(4)oeⅦ〉q,利用多模压缩态理论研究了它们的等N次幂H压缩,结果发现:态|Ψoe(4)Ⅵ〉q和|Ψ(4)oeⅦ〉q具有完全相同的等N次幂H压缩规律;当压缩幂次N与腔模总数q之积,即qN为偶数时,态|Ψoe(4)Ⅵ〉q和|Ψ(4)oeⅦ〉q恒处于等幂次N-H最小测不准态或呈现"半相干态效应";当qN为奇数时,在不同条件下,态|Ψoe(4)Ⅵ〉q和|Ψ(4)oeⅦ〉q可以呈现三种不同状态:第一正交分量呈现等N次幂H压缩;第二正交分量呈现等N次幂H压缩; 可呈现"半相干态效应". 相似文献
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一种新型的多模虚偶相干态光场的等阶N次方Y压缩与等阶N次方H压缩 总被引:45,自引:25,他引:20
本文利用新近建立的多模压缩态理论,详细研究了一种新型的多模虚偶相干态光场|Ψi,e(2)>q的广义非线性等阶N次方Y压缩与等阶N次方H压缩特性.结果发现:1)态|Ψi,e(2)>q是一种典型的多模非经典光场,当压缩阶数N为奇数时,态|Ψi,e(2)>q在一定条件下总可呈现出周期性变化的、任意阶的等阶N次方Y压缩效应;当腔模总数q与压缩阶数N这两者的乘积q·N为奇数时,则在一定条件下态|Ψi,e(2)>q又可呈现出周期性变化的、任意阶的等阶N次方H压缩效应.2)态|Ψi,e(2)>q的等阶N次方Y压缩与等阶N次方H压缩效应这两者的压缩程度和压缩深度分别与几率幅γq(e)、压缩参数Rj、各模的初始相位φj(或者各模的初始相位和 φj)、压缩阶数N以及腔模(指纵模)总数q等呈较强的非线性关联,等阶N次方H压缩效应与上述诸参量之间的非线性关联程度要比等阶N次方Y压缩效应的更强.3)多模虚偶相干态光场|Ψi,e(2)>q与多模偶相干态光场|Ψ,e>q及多模复共轭偶相干态光场|Ψ*,e(2)>q这后两者的等阶N次方Y压缩效应和等阶N次方H压缩效应的压缩条件和压缩特性正好相反,这种现象就称为相反压缩. 相似文献
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对应变GaN/AlxGa1-xN异质结系统,考虑理想界面突变势垒,引入简化相干势近似,采用变分法讨论了流体静压力下外界电场对束缚于界面附近的浅杂质态结合能的影响.对GaN为衬底的闪锌矿应变异质结,分别计算了(001)和(111)取向时杂质态的结合能随压力、杂质位置、电场强度以及组分的变化关系.结果表明,杂质态结合能随流体静压力呈近线性变化.电场对杂质态的Stark效应则随杂质位置不同而呈现谱线蓝、红移动.此外,还讨论了在不同压力情况下,Al组分对杂质结合能的影响.当杂质处于GaN材料中且距界面较远时,Al组分的增加使电子的二维特性增强,从而使结合能增大,且压力加剧增幅的增加;当杂质处于AlxGa1-xN材料中,Al组分的增加削弱了杂质与电子间的库仑相互作用,故而结合能降低.
关键词:
xGa1-xN异质结')" href="#">GaN/AlxGa1-xN异质结
杂质态
压力
Stark效应 相似文献
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Aram Kh. Manaselyan Albert A. Kirakosyan 《Physica E: Low-dimensional Systems and Nanostructures》2005,28(4):462-470
Within the framework of effective mass approximation and variational method, the electronic and impurity states in spherical quantum dots with convex bottom in magnetic field are calculated. Calculations are carried out both for on-center and off-center impurities. The impurity binding energy dependencies on radius, measure of convexity of quantum dot bottom, impurity position and magnetic field induction are obtained for the Ga1-xAlxAs/Ga1-yAlyAs system. 相似文献
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I investigated a detailed study of persistent current and low-field magnetic susceptibility in one-dimensional mesoscopic rings and cylinders threaded by slowly varying magnetic flux φ in the tight-binding model. In perfect rings described by constant number of electrons Ne, current shows only saw-tooth variation with φ, while for those rings described by constant chemical potential μ, current varies saw-tooth like for some special choices of μ, but in all other cases it shows kink-like structures. On the other hand, in perfect cylinders I get both saw-tooth and kink-like structures in persistent current whether these cylinders are described by constant Ne or μ. In presence of impurity, current gets a continuous variation with φ only for the rings described by constant Ne, while in all other cases it depends on the choice of μ. My exact calculation predicts that the diamagnetic and paramagnetic sign of the low-field currents can be determined exactly for the rings described by constant Ne. In perfect rings, I get only diamagnetic currents both for odd and even Ne, while in presence of impurity current always shows diamagnetic sign for the rings with odd Ne and paramagnetic sign for the rings with even Ne. Both for the perfect and disordered rings described by constant μ the sign of the current cannot be mentioned exactly since it depends on the choice of μ and disordered configurations. Similar arguments are also true for the cylinders those are described either by constant Ne or by constant μ since the sign of the current in these systems depends on Ne, μ and disordered configurations. 相似文献
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Intervalley rate transfer along 〈100〉 directions is deduced from conductivity measurements versus electric field for different impurity concentrations ND-NA at lattice temperatures T ? 77 K. The maximum rate transfer plotted versus T reaches 1 at T < 25 K and does not depend on ND-ND for ND-NA ? 2 × 1014crmcm?3. 相似文献
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S.-H. Dong 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2000,11(2):159-165
In terms of the modified Sturm-Liouville theorem, the Levinson theorem for the one-dimensional Klein-Gordon equation with
a symmetric potential V(x) is established. It is shown that the number N+ (N-) of bound states with even (odd) parity is related to the phase shift of the scattering states with the same parity at zero momentum as and The solution of the one-dimensional Klein-Gordon equation with the energy M or -M is called as a half bound state if it is finite but does not decay fast enough at infinity to be square integrable.
Received 22 December 1999 相似文献
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E. Papp C. Micu L. Aur D. Racolta 《Physica E: Low-dimensional Systems and Nanostructures》2007,36(2):178-183
One shows that the oscillations with respect to the magnetic flux in the one-dimensional discretized Aharonov–Bohm rings are sensitive with respect to the parity of the number of electrons Ne. Resorting to basic flux intervals of unit length indicates that the period of such oscillations is given by the flux quantum Φ0=hc/e and by 2Φ0 if Ne is odd and even, respectively. Accordingly, one deals with a period doubling effect when passing from odd Ne-values to even ones, which may be useful in the design of further nanodevices. Interaction free limits of the Drude weight are also discussed. 相似文献
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Summary The unmixing transition of both symmetrical polymer blends AB (i.e. chain lengthsN
A=N
B=N) and asymmetrical ones (N
B/N
A=2,3) is studied by large-scale Monte Carlo simulations of the bond fluctuation model. Combination of semi-grand-canonical
simulation techniques, ?histogram reweighting? and finitesize scaling allows an accurate location of the coexistence curve
in the critical region. The variation of the critical temperature with chain length (N) is studied and compared to theoretical predictions. For the symmetrical case, use of chain lengths up toN=512 allows a rough estimation of crossover scaling functions for the crossover from Ising to mean-field exponents. The order-disorder
transitions in melts of both symmetric (compositionf=N
A/(N
A+N
B)=1/2) and asymmetric (f=3/4) block copolymers is studied for very short chains (16≤N≤60). The interplay between structure and chain configuration is emphasized. Qualitative evidence for ?dumbell formation?
of chains and vacancy enrichment in A-B-interfaces and near hard walls is presented.
Paper presented at the I International Conference on Scaling Concepts and Complex Fluids, Copanello, Italy, July 4–8, 1994. 相似文献