Publications (9)
Flopping-mode electric dipole spin resonance in phosphorus donor qubits in silicon
F. N. Krauth, S. K. Gorman, Y. He +9
Single spin qubits based on phosphorus donors in silicon are a promising candidate for a large-scale quantum computer. Despite long coherence times, achieving uniform magnetic cont…
Dressed-state amplification by a superconducting qubit
G. Oelsner, P. Macha, O. V. Astafiev +6
We demonstrate amplification of a microwave signal by a strongly driven two-level system in a coplanar waveguide resonator. The effect known from optics as dressed-state lasing is…
Strong Coupling of a Quantum Oscillator to a Flux Qubit at its Symmetry Point
A. Fedorov, A. K. Feofanov, P. Macha +3
A flux qubit biased at its symmetry point shows a minimum in the energy splitting (the gap), providing protection against flux noise. We have fabricated a qubit whose gap can be tu…
Tuned transition from quantum to classical for macroscopic quantum states
A. Fedorov, P. Macha, A. K. Feofanov +2
The boundary between the classical and quantum worlds has been intensely studied. It remains fascinating to explore how far the quantum concept can reach with use of specially fabr…
Weak continuous monitoring of a flux qubit using coplanar waveguide resonator
G. Oelsner, S. H. W. van der Ploeg, P. Macha +9
We study a flux qubit in a coplanar waveguide resonator by measuring transmission through the system. In our system with the flux qubit decoupled galvanically from the resonator, t…
Losses in coplanar waveguide resonators at millikelvin temperatures
P. Macha, S. H. W. van der Ploeg, G. Oelsner +4
We study the loss rate for a set of lambda/2 coplanar waveguide resonators at millikelvin temperatures (20 mK - 900mK) and different applied powers (3E-19 W - 1E-12 W). The loss ra…
Amplification and attenuation of a probe signal by doubly-dressed states
S. N. Shevchenko, G. Oelsner, Ya. S. Greenberg +6
We analyse a system composed of a qubit coupled to electromagnetic fields of two high quality quantum oscillators. Particular realization of such a system is the superconducting qu…
Spectroscopy of a Qubit Array via a Single Transmission Line
M. Jerger, S. Poletto, P. Macha +4
Frequency-selective readout for superconducting qubits opens the way towards scaling qubit circuits up without increasing the number of measurement lines. Here we demonstrate the r…
Impact of measurement backaction on nuclear spin qubits in silicon
S. Monir, E. N. Osika, S. K. Gorman +7
Phosphorus donor nuclear spins in silicon couple weakly to the environment making them promising candidates for high-fidelity qubits. The state of a donor nuclear spin qubit can be…