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arXiv 2301.06004quant-phcond-mat.stat-mechhep-thmath-phmath.MP
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非厄米 $\mathscr{PT}$ 对称海森堡自旋链的精确解

Exact solution of a non-Hermitian $\mathscr{PT}$-symmetric Heisenberg spin chain

Pradip Kattel, Parameshwar R. Pasnoori, Natan Andrei

AI总结:

本文构造了具有可积边界场的非厄米PT对称海森堡自旋链的精确解,揭示出A、B两类相及其子相,并分析了PT对称破缺与边界束缚态的关联。

摘要:

我们构造了一个具有可积边界场的非厄米 $\mathscr{PT}$ 对称各向同性海森堡自旋链的精确解。我们发现该系统表现出两种类型的相,分别称为 $A$ 相和 $B$ 相。在 $B$ 型相中,$\mathscr{PT}$ 对称性保持不破缺,仅由能量全为实数的本征态组成;而 $A$ 型相包含一个 $\mathscr{PT}$ 对称性破缺的部分,该部分仅由能量全为复数的本征态组成,同时还包含一个 $\mathscr{PT}$ 对称性不破缺的部分,其本征态能量为实数。$\mathscr{PT}$ 对称性破缺的部分由成对的本征态组成,这些本征态的能量互为复共轭。$A$ 型相中两个部分的存在与边界处具有复能量的指数局域束缚态有关,这些束缚态由边界弦描述。我们发现 $A$ 型和 $B$ 型相都可以进一步细分为表现出不同基态的子相。我们还计算了单磁振子部分中的束缚态波函数,发现随着边界参数虚部的增大,指数局域波函数会变宽,从而更多地延伸到体内部,这表明对于较大的边界参数虚部值,指数局域束缚态可能无法稳定存在。

英文摘要:

We construct the exact solution of a non-Hermitian $\mathscr{PT}$-symmetric isotropic Heisenberg spin chain with integrable boundary fields. We find that the system exhibits two types of phases we refer to as $A$ and $B$ phases. In the $B$ type phase, the $\mathscr{PT}$- symmetry remains unbroken and it consists of eigenstates with only real energies, whereas the $A$ type phase contains a $\mathscr{PT}$-symmetry broken sector comprised of eigenstates with only complex energies and a sector of unbroken $\mathscr{PT}$-symmetry with eigenstates of real energies. The $\mathscr{PT}$-symmetry broken sector consists of pairs of eigenstates whose energies are complex conjugates of each other. The existence of two sectors in the $A$ type phase is associated with the exponentially localized bound states at the edges with complex energies which are described by boundary strings. We find that both $A$ and $B$ type phases can be further divided into sub-phases which exhibit different ground states. We also compute the bound state wavefunction in one magnon sector and find that as the imaginary value of the boundary parameter is increased, the exponentially localized wavefunction broadens thereby protruding more into the bulk, which indicates that exponentially localized bound states may not be stabilized for large imaginary values of the boundary parameter.

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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