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The Birth, Care, and Feeding of Cat States in Circuit QED: Quantum Jumps of Photon Parity

Event Details

Event Dates: 

Wednesday, September 10, 2014 - 4:00pm

Seminar Location: 

  • Duane Physics Room G1B20

Speaker Name(s): 

Rob Schoelkopf

Speaker Affiliation(s): 

Yale University
Seminar Type/Subject

Scientific Seminar Type: 

  • Physics Department Colloquium

Event Details & Abstract: 

Dramatic progress has been made in the last decade and a half towards realizing solid-state systems for quantum information processing with superconducting quantum circuits. Artificial atoms (or qubits) based on Josephson junctions have improved their coherence times more than a million-fold, have been entangled, and used to perform simple quantum algorithms. The next challenge for the field is demonstrating quantum error correction that actually improves the lifetimes, a necessary step for building more complex systems. I will describe recent experiments with superconducting circuits, where we store quantum information in the form of Schrodinger cat states of a microwave cavity, containing up to 100 photons. Using an ancilla qubit, we then monitor the gradual death of these cats, photon by photon, by observing the first jumps of photon number parity. This represents the first continuous observation of a quantum error syndrome, and may enable new approaches to quantum information based on photonic qubits.