I'm wondering, doesn't the concept of temperature change with pressure? For example, homemade fusion reactors operate at low pressures but at a temperature higher than the sun. So, if this circuit is operating at a high pressure, then isn't surrounding room temperature relatively low? At the mechanical level, a substance held between carbon diamond anvils isnt free to change momentum or kinetic energy due to the kinetic impacts of room temperature air, vapor, or plasma.
Second question, do virtual particles have the same Casimir effects in this apparatus, as we would see in low pressure experiments? If you're interested, also checkout the results published recently on measuring the Casimir force. Reference: “Casimir spring and dilution in macroscopic cavity optomechanics” by J. M. Pate, M. Goryachev, R. Y. Chiao, J. E. Sharping and M. E. Tobar, 3 August 2020, Nature Physics.
DOI: 10.1038/s41567-020-0975-9