Josephson quantum computing device and integrated circuit using such devices

A Josephson quantum computing device, characterized in that it comprises:

• a superconducting ring member having a π-junction and a 0-junction;
• and
• a quantum state detecting member constituted by a superconducting quantum interference device arranged outside of said superconducting ring member, wherein:
• a bonding and antibonding state brought about by a tunneling effect between a |↑> and a |↓> state as two states degenerate in energy of said superconducting ring member are regarded as quantum bits, and
• said bonding and antibonding states as the quantum bits are read out by said quantum state detecting member.

An integrated circuit using Josephson quantum computing devices, characterized in that each of said Josephson quantum computing devices comprises:

• a superconducting ring member having a π-junction constituted of a Josephson junction and a first 0-junction or a first and a second 0-junction each of which is constituted of a Josephson junction;
• and
• a quantum state detecting member constituted by a superconducting quantum interference device arranged outside of said superconducting ring member, wherein:
• a bonding and an antibonding state brought about by a tunneling effect between a |↑> and a |↓> state as two states degenerate in energy of said superconducting ring member are regarded as quantum bits, and
• said bonding and antibonding states as the quantum bits are read out by said quantum state detecting member.