Characterization of barrier-tunable radio-frequency-SQUID for Maxwell’s demon experiment<xref rid="cpb_27_6_068501_fn1" ref-type="fn">*</xref> <fn id="cpb_27_6_068501_fn1"> <label>*</label> <p>Project supported by the National Natural Science Foundation of China (Grant No. 11653001), the National Basic Research Program of China (Grant No. 2011CBA00304), the Tsinghua University Initiative Scientific Research Program, China (Grant No. 20131089314), and the Zhejiang Tianjingsheng Foundation, China, for Student Assistantships (Gang Li and Hao Li).</p> </fn>

Characterization of barrier-tunable radio-frequency-SQUID for Maxwell’s demon experiment* *

Project supported by the National Natural Science Foundation of China (Grant No. 11653001), the National Basic Research Program of China (Grant No. 2011CBA00304), the Tsinghua University Initiative Scientific Research Program, China (Grant No. 20131089314), and the Zhejiang Tianjingsheng Foundation, China, for Student Assistantships (Gang Li and Hao Li).

Li Gang¹, Dhamala Suman², Li Hao¹, Liu JianShe¹, Chen Wei^{1, †}

(color online) (a) Schematic diagram of CJJ RF-SQUID qubit with an overdamped DC-SQUID used to monitor the state of qubit. I_bias is the bias current of DC-SQUID. V_out is the output voltage of DC-SQUID. ϕ and ϕ_x are the total and external flux applied to the RF-SQUID loop. ϕ_CJJ is the external flux applied to the compound Josephson junction. ϕ_sq is the external flux applied to the DC-SQUID loop. ϕ_x tilts the potential and ϕ_CJJ raises and lowers the barrier between the wells. (b) Potential of the RF-SQUID as a function of ϕ. ΔU_L (ΔU_R) is the barrier seen from the left (right) well and ϵ is the energy difference between the two potential minima (positive in this case). (c) Sketch of energy diagrams for the operation cycle of Maxwell demon.