Coupler and calculating device

A coupler, comprising:

• a first capacitor including a first capacitor end portion and a first capacitor other-end portion;
• a first inductor including
• a first inductor end portion electrically connected with the first capacitor end portion, and
• a first inductor other-end portion;
• a second capacitor including a second capacitor end portion and a second capacitor other-end portion;
• a second inductor including
• a second inductor end portion electrically connected with the second capacitor end portion, and
• a second inductor other-end portion electrically connected with the first capacitor other-end portion, the first inductor other-end portion, and the second capacitor other-end portion;
• and
• a first Josephson junction including
• a first Josephson junction end portion electrically connected with the first capacitor end portion, and
• a first Josephson junction other-end portion electrically connected with the second capacitor end portion,
• a space being surrounded with the first inductor, the second inductor, and the first Josephson junction,
• the first capacitor end portion being couplable with a first nonlinear resonator, and
• the second capacitor end portion being couplable with a second nonlinear resonator.