论文标题
使用S-矩阵形式主义研究热气中的结合状态
Study of bound states in a thermal gas using the S-matrix formalism
论文作者
论文摘要
我们已经研究了在量子场理论（QFT）的情况下，在热气中的结合状态的形成。我们已经考虑了具有$φ^4 $相互作用的标量QFT，其中$φ$是带有质量$ m $的标量粒子。当耦合常数为负并且其模量大于某个临界值时，我们已经观察到形成$φ$ - $φ$类型的结合状态。我们通过使用S-矩阵形式主义计算了结合状态对系统热气体压力的贡献。我们的分析基于一种单位化的单循环方法，该方法是该理论是有限且针对耦合常数的每个值的良好定义的。我们已经观察到，在临界耦合时，总压力与耦合常数的函数也是连续的：由于结合状态的突然出现而导致的压力跳跃完全取消了相互作用对压力的相互作用贡献的类似跳跃（但具有相反的符号）。
We have studied the formation of bound states in a thermal gas in the context of quantum field theory (QFT). We have considered a scalar QFT with $φ^4$ interaction, where $φ$ is a scalar particle with mass $m$. We have observed the formation of a bound state of $φ$-$φ$ type when the coupling constant is negative and its modulus is larger than a certain critical value. We have calculated the contribution of the bound state to the pressure of the thermal gas of the system by using the S-matrix formalism. Our analysis is based on a unitarized one-loop resumed approach in which the theory is finite and well defined for each value of the coupling constant. We have observed that the total pressure as a function of the coupling constant is continuous also at the critical coupling: the jump in pressure due to the sudden appearance of the bound state is exactly cancelled by an analogous jump (but with opposite sign) of the interaction contribution to the pressure.
