Measurement of the Boltzmann constant by Johnson noise thermometry using a superconducting integrated circuit

Abstract

We report on our measurement of the Boltzmann constant by Johnson noise thermometry (JNT) using an integrated quantum voltage noise source (IQVNS) that is fully implemented with superconducting integrated circuit technology. The IQVNS generates calculable pseudo white noise voltages to calibrate the JNT system. The thermal noise of a sensing resistor placed at the temperature of the triple point of water was measured precisely by the IQVNSbased JNT. We accumulated data of more than 429 200 s in total (over 6 d) and used the Akaike information criterion to estimate the fitting frequency range for the quadratic model to calculate the Boltzmann constant. Upon detailed evaluation of the uncertainty components, the experimentally obtained Boltzmann constant was k = 1.380 6436 × 10-23 J K-1 with a relative combined uncertainty of 10.22 × 10-6. The value of k is relatively -3.56 × 10-6 lower than the CODATA 2014 value (Mohr et al 2016 Rev. Mod. Phys. 88 035009).