Observation of quantum jumps in a superconducting artificial atom

A continuously monitored quantum system prepared in an excited state will decay to its ground state with an abrupt jump. The jump occurs stochastically on a characteristic time scale T1, the lifetime of the excited state. These quantum jumps, originally envisioned by Bohr, have been observed in trapped atoms and ions, single molecules, photons, and single electrons in cyclotrons. Here we report the first observation of quantum jumps in a macroscopic quantum system, in our case a superconducting "artificial atom" or quantum bit (qubit) coupled to a superconducting microwave cavity. We use a fast, ultralow-noise parametric amplifier to amplify the microwave photons used to probe the qubit state, enabling continuous high-fidelity monitoring of the qubit. This technique represents a major step forward for solid state quantum information processing, potentially enabling quantum error correction and feedback, which are essential for building a quantum computer. Our technology can also be readily integrated into hybrid circuits involving molecular magnets, nitrogen vacancies in diamond, or semiconductor quantum dots.Comment: Updated draft including supplementary information. 8 pages, 6 figures. Supplementary videos are available on our website at http://physics.berkeley.edu/research/siddiqi/docs/supps

Studies in Sindi society the anthropology of selected Sindi communities

The purpose of this thesis is to accept the fact that there is a territory called Sind which has possessed and still possesses a regional identity and then to examine the nature of society within it. The emphasis throughout is on social and cultural characteristics related as far as possible to the various forces affecting them and operating within them, a field of study lying between Social Geography and Social Anthropology. Within Sind there exist diversities of religion, of occupation and economy but overriding these there has been until recently an undisputed social and cultural unity manifesting itself in language folk customs, mysticism and a class / caste division of society. This unity has been associated with subsistenceorientated agricultural economy in which family and kinship have aided survival in a harsh a rid environment. Sind has been a region peripheral to the mainstream of Asian change and regional and social unity remained undisturbed for centuries. Two phenomena have recently disturbed this traditional continuity, first the effects of partition of All - India and secondly urbanization in the developing state of Pakistan. The question remains whether traditional rural - based unity will remain dominant or whether a new hybrid culture will appea

Cyclic Strength Evaluation of Rockfill Dams

A method of modeling the cyclic behavior of gravelly soils containing particles too large to be tested in standard laboratory equipment has been described. This matrix model is based on the understanding that oversize particles floating in a matrix of smaller grains can be removed without significantly affecting the cyclic behavior of the total soil. Successful modeling of the total soil requires that the matrix be tested at the same relative density as that of the total material. Cyclic triaxial test results on two different gravelly soils are presented. Results of tests performed on the total soil with maximum grain size of 2 in. are accurately predicted by cyclic tests on smaller samples of matrix soil with 0.5 in. maximum grain size

Quantum Fluctuations in the Chirped Pendulum

An anharmonic oscillator when driven with a fast, frequency chirped voltage pulse can oscillate with either small or large amplitude depending on whether the drive voltage is below or above a critical value-a well studied classical phenomenon known as autoresonance. Using a 6 GHz superconducting resonator embedded with a Josephson tunnel junction, we have studied for the first time the role of noise in this non-equilibrium system and find that the width of the threshold for capture into autoresonance decreases as the square root of T, and saturates below 150 mK due to zero point motion of the oscillator. This unique scaling results from the non-equilibrium excitation where fluctuations, both quantum and classical, only determine the initial oscillator motion and not its subsequent dynamics. We have investigated this paradigm in an electrical circuit but our findings are applicable to all out of equilibrium nonlinear oscillators.Comment: 5 pages, 4 figure

Transition Metal Complexes of a-Naphthylamine Dithiocarbamate

a-Naphthylamine dithiocarbamate and its complexes with Co(II), Ni(U), Cu(II), Ru(III) , Rh(III), Pd(II), Pt(IV), Zn(II), Cd(II) and Hg(II) have been prepared and characterized by chemical analysis, IR - and reflectance spectral studies and magnetic susceptibili ty measurements. In all these complexes the dithiocarbamato moiety acts as a chelate. The Ni(II), Cu(II) and Pd(Il) complexes have been found to be square planar while those of Ru(III), Rh(III) and Pt(IV) were proposed to be octahedral in nature. The Co(II) ion seems to have a tetrahedral geometry, unlike the other known square planar dithiocarbamato complexes of Co(II). No definite structure, however, could be proposed for Zn(II), Cd(II) and Hg(II) on the basis of limited studies

Millikelvin thermal and electrical performance of lossy transmission line filters

We report on the scattering parameters and Johnson noise emission of low-pass stripline filters employing a magnetically loaded silicone dielectric down to 25 mK. The transmission characteristic of a device with $f_{-3dB}$=1.3 GHz remains essentially unchanged upon cooling. Another device with $f_{-3dB}$=0.4 GHz, measured in its stopband, exhibits a steady state noise power emission consistent with a temperature difference of a few mK relative to a well-anchored cryogenic microwave attenuator at temperatures down to 25 mK, thus presenting a matched thermal load.Comment: 4 pages, 4 figure