Probing individual tunneling fluctuators with coherently controlled tunneling systems

Josephson junctions made from aluminium and its oxide are the most commonly used functional elements for superconducting circuits and qubits. It is generally known that the disordered thin-film AlOx contains atomic tunneling systems. Coherent tunneling systems may couple strongly to a qubit via their electric dipole moment, giving rise to spectral level repulsion. In addition, slowly fluctuating tunneling systems are observable when they are located close to coherent ones and distort their potentials. This interaction causes telegraphic switching of the coherent tunneling systems' energy splitting. Here, we measure such switching induced by individual fluctuators on time scales from hours to minutes using a superconducting qubit as a detector. Moreover, we extend the range of measurable switching times to millisecond scales by employing a highly sensitive single-photon qubit swap spectroscopy and statistical analysis of the measured qubit states.

[1]  Thomas Hellman.  PHIL , 2018, Encantado.

[2]  Juhn-Jong Lin,et al.  Probing nanocrystalline grain dynamics in nanodevices , 2017, Science Advances.

[3]  Y. Salathe,et al.  Rapid High-Fidelity Single-Shot Dispersive Readout of Superconducting Qubits , 2017, 1701.06933.

[4]  A. Shnirman,et al.  Decoherence of a quantum two-level system by spectral diffusion , 2016, 1602.01453.

[5]  A. Shnirman,et al.  Decoherence spectroscopy with individual two-level tunneling defects , 2016, Scientific Reports.

[6]  A. Burin,et al.  Low-temperature1/fnoise in microwave dielectric constant of amorphous dielectrics in Josephson qubits , 2015, 1503.02646.

[7]  Stefano Poletto,et al.  Interacting two-level defects as sources of fluctuating high-frequency noise in superconducting circuits , 2015, 1503.01637.

[8]  J. Cole,et al.  Observation of directly interacting coherent two-level systems in an amorphous material , 2015, Nature Communications.

[9]  L. Ioffe,et al.  Interacting tunneling model for two-level systems in amorphous materials and its predictions for their dephasing and noise in superconducting microresonators , 2014, 1404.2410.

[10]  V. A. Tulin,et al.  Evidence for interacting two-level systems from the 1/f noise of a superconducting resonator , 2013, Nature Communications.

[11]  A. Ustinov,et al.  Strain Tuning of Individual Atomic Tunneling Systems Detected by a Superconducting Qubit , 2012, Science.

[12]  Elliot L Elson,et al.  Fluorescence correlation spectroscopy: past, present, future. , 2011, Biophysical journal.

[13]  F. Wellstood,et al.  Loss Dependence on Geometry and Applied Power in Superconducting Coplanar Resonators , 2010, IEEE Transactions on Applied Superconductivity.

[14]  J. Cole,et al.  Measuring the temperature dependence of individual two-level systems by direct coherent control. , 2010, Physical review letters.

[15]  A. Ustinov,et al.  High-contrast readout of superconducting qubits beyond the single-shot resolution limit , 2007 .

[16]  M. Steffen,et al.  State tomography of capacitively shunted phase qubits with high fidelity. , 2006, Physical review letters.

[17]  H. B. Weber,et al.  Mechanically controlled tunneling of a single atomic defect , 2001 .

[18]  R. Egger,et al.  CROSSOVER FROM COHERENT TO INCOHERENT DYNAMICS IN DAMPED QUANTUM SYSTEMS , 1997, cond-mat/9702115.

[19]  R. Weis,et al.  Cross-over to incoherent tunnelling of substitutional defects in alkali halide crystals , 1996 .

[20]  Birge,et al.  Dissipative quantum tunneling of a single defect in Bi. , 1993, Physical review. B, Condensed matter.

[21]  B. Halperin,et al.  Spectral diffusion, phonon echoes, and saturation recovery in glasses at low temperatures , 1977 .

[22]  J. Jäckle.  On the ultrasonic attenuation in glasses at low temperatures , 1972 .

[23]  W. A. Phillips,et al.  Tunneling states in amorphous solids , 1972 .

[24]  J. Coolidge,et al.  An Introduction to Mathematical Probability , 1925 .

[25]  P. Anderson,et al.  Anomalous low-temperature thermal properties of glasses and spin glasses , 1972 .