Editing Josephson effect (section)

===The inverse AC Josephson effect===
Microwave radiation of a single [[Angular frequency|(angular) frequency]] <math>\omega</math> can induce quantized DC voltages<ref>{{Cite journal |last1=Langenberg |first1=D. N. |last2=Scalapino |first2=D. J. |last3=Taylor |first3=B. N. |last4=Eck |first4=R. E. |date=1966-04-01 |title=Microwave-induced D.C. voltages across Josephson junctions |journal=Physics Letters |volume=20 |issue=6 |pages=563–565 |doi=10.1016/0031-9163(66)91114-0 |bibcode=1966PhL....20..563L |issn=0031-9163}}</ref> across the Josephson junction, in which case the Josephson phase takes the form <math>\varphi (t) =  \varphi_0 + n \omega t + a \sin(\omega t)</math>, and the voltage and current across the junction will be:
<math display="block">V(t) = \frac{\hbar}{2 e} \omega ( n + a \cos( \omega t) ), \text{ and } I(t) = I_c \sum_{m = -\infty}^\infty J_m (a) \sin (\varphi_0 + (n + m) \omega t),</math>

The DC components are:
<math display="block">V_\text{DC} = n \frac{\hbar}{2 e} \omega, \text{ and } I_\text{DC} = I_c J_{-n} (a) \sin \varphi_0.</math>

This means a Josephson junction can act like a perfect frequency-to-voltage converter,<ref>{{Cite journal |last1=Levinsen |first1=M. T. |last2=Chiao |first2=R. Y. |last3=Feldman |first3=M. J. |last4=Tucker |first4=B. A. |date=1977-12-01 |title=An inverse ac Josephson effect voltage standard |journal=Applied Physics Letters |volume=31 |issue=11 |pages=776–778 |doi=10.1063/1.89520 |bibcode=1977ApPhL..31..776L |issn=0003-6951}}</ref> which is the theoretical basis for the Josephson voltage standard.