Noise and loss of superconducting aluminium resonators at single photon energies

The loss and noise mechanisms of superconducting resonators are useful tools for understanding decoherence in superconducting circuits. While the loss mechanisms have been heavily studied, noise in superconducting resonators has only recently been investigated. In particular, there is an absence of literature on noise in the single photon limit. Here, we measure the loss and noise of an aluminium on silicon quarter-wavelength ($\lambda/4$) resonator in the single photon regime.Comment: LT28 Conference proceeding, to be published in IOP Conference Serie

Comparison of Single-Grip Harvester Productivity in Clear- and Shelterwood Cutting

An increased interest in the use of shelterwood stands to promote regeneration has led to an interest in how singlegrip harvester productivity is affected by shelterwood cutting compared to clearcutting. A comparative time study of a large singlegrip harvester was made in a spruce stand in northern Sweden. Three treatments were used. Shelterwood cutting leaving: 1) a sparse stand, 2) a dense residual stand, and 3) clearcutting. Each treatment was replicated three times. Results show that productivity decreases from 64 m3 per effective hour in clearcutting to 54 and 41 m3 per effective hour when shelterwoods with 259 and 381 stems ha1, respectively, were retained

Labor Supply Responses to New Rural Social Pension Insurance in China: A Regression Discontinuity Approach

Transitioning into retirement is an under-researched phenomenon in developing countries. Largely, this is linked to a predominance of contexts where – in particular – the rural population remains outside the coverage of any formal pension system. In 2008, China introduced the New Rural Social Pension (NRSP), a program which by now covers the majority of the Chinese rural elderly. This paper examines the effects of the NRSP on the labor supply of the elderly in rural China. As pension benefit eligibility at the time of its implementation is conditional on age, a regression discontinuity design is applied to investigate the casual effect of the receipt of pension benefits on labor supply. Furthermore, as the NRSP is neither means-tested nor conditions on retirement, it induces a pure income effect on employment. Using data from the China Health and Retirement Longitudinal Study, a nationally representative data set, we find that the receipt of pension benefits increases the probability of retirement among the rural elderly by around 15%

Period-tripling subharmonic oscillations in a driven superconducting resonator

We have observed period-tripling subharmonic oscillations, in a superconducting coplanar waveguide resonator operated in the quantum regime, $k_B T \ll \hbar\omega$. The resonator is terminated by a tunable inductance that provides a Kerr-type nonlinearity. We detected the output field quadratures at frequencies near the fundamental mode, $\omega/2\pi \sim 5\,$GHz, when the resonator was driven by a current at $3\omega$ with an amplitude exceeding an instability threshold. The output radiation was red-detuned from the fundamental mode. We observed three stable radiative states with equal amplitudes and phase-shifted by $120^\circ$. The downconversion from $3\omega$ to $\omega$ is strongly enhanced by resonant excitation of the second mode of the resonator, and the cross-Kerr effect. Our experimental results are in quantitative agreement with a model for the driven dynamics of two coupled modes

Labor Supply Responses to New Rural Pension Insurances in China: A Regression Discontinuity Approach

Transitioning into retirement is an under-researched phenomenon in developing countries. Largely, this is linked to a predominance of contexts where –in particular –the rural population remains outside the coverage of any formal pension system. In 2008, China introduced the New Rural Social Pension (NRSP), a program which by now covers the majority of the Chinese rural elderly. This paper examines the effects of the NRSP on the labor supply of the elderly in rural China. As pension benefit eligibility at the time of its implementation is conditional on age, a regression discontinuity design is applied to investigate the casual effect of the receipt of pension benefits on labor supply. Furthermore, as the NRSP isneither means-tested nor conditions on retirement, it induces a pure income effect on employment. Using data from the China Health and Retirement Longitudinal Study, a nationally representative data set, we find that the receipt of pension benefitsincreases the probability of retirement among the rural elderly by around 15%

Decoherence benchmarking of superconducting qubits

We benchmark the decoherence of superconducting qubits to examine the temporal stability of energy-relaxation and dephasing. By collecting statistics during measurements spanning multiple days, we find the mean parameters $\overline{T_{1}}$ = 49 $\mu$s and $\overline{T_{2}^{*}}$ = 95 $\mu$s, however, both of these quantities fluctuate explaining the need for frequent re-calibration in qubit setups. Our main finding is that fluctuations in qubit relaxation are local to the qubit and are caused by instabilities of near-resonant two-level-systems (TLS). Through statistical analysis, we determine switching rates of these TLS and observe the coherent coupling between an individual TLS and a transmon qubit. Finally, we find evidence that the qubit's frequency stability is limited by capacitance noise. Importantly, this produces a 0.8 ms limit on the pure dephasing which we also observe. Collectively, these findings raise the need for performing qubit metrology to examine the reproducibility of qubit parameters, where these fluctuations could affect qubit gate fidelity.Comment: 15 pages ArXiv version rev

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ИНОСТРАННЫЕ СТУДЕНТЫВОСПИТАТЕЛЬНАЯ РАБОТ

Period multiplication in a parametrically driven superconducting resonator

We report on the experimental observation of period multiplication in parametrically driven tunable superconducting resonators. We modulate the magnetic flux through a superconducting quantum interference device, attached to a quarter-wavelength resonator, with frequencies $n\omega$ close to multiples, $n=2,\,3,\,4,\,5$, of the resonator fundamental mode and observe intense output radiation at $\omega$. The output field manifests $n$-fold degeneracy with respect to the phase, the $n$ states are phase shifted by $2\pi/n$ with respect to each other. Our demonstration verifies the theoretical prediction by Guo et al. in PRL 111, 205303 (2013), and paves the way for engineering complex macroscopic quantum cat states with microwave photons

Dynamic Description with Computer Supported Pictures

A methodology was developed and tested in six case studies at four medium-sized manufacturing companies within the machine engineering industry. Existing and planned work environments and production processes were described with the aid of computer-generated pictures. The pictures were used within the framework of an action research methodology in which managers and those employees affected, together with trade unions and company health care representatives, cooperated to establish the preconditions for improved planning from the point of view of both productivity and work environment. The picture methodology using animated pictures, developed to create and present two- and three-dimensional views of a computer model with manipulable objects, was tested both in a workshop with 20 participants from manufacturing companies and corporate health care and in an experimental study with 30 psychology students as experimental subjects. At a Community College with an artistic bet, the way in which different groups within the college described its organization with the aid of pictures and symbols was studied