We have classified the superposition of squeezed wavepackets into two kinds and studied their quadrature squeezing. We have shown that the squeezing and higher-order squeezing in the quadrature disappear for the states of the first kind. However, for the second kind, it is possible to achieve the maximum amount of squeezing by adjusting the parameters in the superposition. The absence of squeezing for the superposition states is explained based on the expectation value of the energy density. We find that the expectation value of energy density in quantum wavepackets that shows no squeezing is positive. We have also studied the relationship between energy density and the squeezing in the decoherence dynamics of single and two-mode squeezed states. Our further analysis shows that different types of squeezed states, including states which are not wavepackets, exhibit negative energy density.

中文翻译：

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叠加态压缩的消失及其在能量密度上的表现

我们将压缩波包的叠加分为两类，研究了它们的正交压缩。我们已经表明，对于第一类状态，正交中的压缩和高阶压缩消失了。而对于第二种，可以通过调整叠加中的参数来达到最大的挤压量。基于能量密度的期望值来解释叠加态不存在挤压。我们发现没有压缩的量子波包中能量密度的期望值为正。我们还研究了单模和双模压缩态的退相干动力学中能量密度与压缩之间的关系。我们的进一步分析表明，不同类型的压缩状态，