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arXiv math-ph/0201013math-phhep-thmath.MP
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一类PT对称振子特征值的实性

On the reality of the eigenvalues for a class of PT-symmetric oscillators

K. C. Shin

摘要:

本文研究了特征值问题-u”(z)-[(iz)^m+P(iz)]u(z)=λu(z),其边界条件是u(z)在z沿射线\arg z=- \frac π{2} \pm \frac{2π}{m+2}趋于无穷远时衰减为零,其中P(z)=a_1 z^{m-1}+a_2 z^{m-2}+. a_{m-1} z是实多项式,m \geq 2。证明了:若对某个1个\leq j \leq \frac{m}{2},对所有1个\leq k \leq m-1,有(j-k)a_k \geq 0,则特征值都是正实的.然后,我们将其锐化为稍大的一类多项式势。特别地,这意味着当α、β和γ都是实数且α \not =0和αγ \geq 0,且边界条件是当z沿正实轴和负实轴趋于无穷大时u(z)衰减到零时,势αiz^3+βz^2+γiz的特征值都是正实的。这验证了Bessis和Zinn-Justin的一个猜想。

英文摘要:

We study the eigenvalue problem -u"(z)-[(iz)^m+P(iz)]u(z)=λu(z) with the boundary conditions that u(z) decays to zero as z tends to infinity along the rays \arg z=-\fracπ{2}\pm \frac{2π}{m+2}, where P(z)=a_1 z^{m-1}+a_2 z^{m-2}+...+a_{m-1} z is a real polynomial and m\geq 2. We prove that if for some 1\leq j\leq\frac{m}{2}, we have (j-k)a_k\geq 0 for all 1\leq k\leq m-1, then the eigenvalues are all positive real. We then sharpen this to a slightly larger class of polynomial potentials. In particular, this implies that the eigenvalues are all positive real for the potentials αiz^3+βz^2+γiz when α,βand γare all real with α\not=0 and αγ\geq 0, and with the boundary conditions that u(z) decays to zero as z tends to infinity along the positive and negative real axes. This verifies a conjecture of Bessis and Zinn-Justin.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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