Virtual photons can mediate interaction between atoms, resulting in an energy shift known as a collective Lamb shift. Observing the collective Lamb shift is challenging, since it can be obscured by ...radiative decay and direct atom-atom interactions. Here, we place two superconducting qubits in a transmission line terminated by a mirror, which suppresses decay. We measure a collective Lamb shift reaching 0.8% of the qubit transition frequency and twice the transition linewidth. We also show that the qubits can interact via the transmission line even if one of them does not decay into it.
We explore routing of propagating phonons in analogy with previous experiments on photons. Surface acoustic waves (SAWs) in the microwave regime are scattered by a superconducting transmon qubit. The ...transmon can be tuned on or off resonance with the incident SAW field using an external magnetic field or the Autler-Townes effect, and thus the reflection and transmission of the SAW field can be controlled in time. We observe 80% extinction in the transmission of the low power continuous signal and a 40 ns rise time of the router. The slow propagation speed of SAWs on solid surfaces allows for in-flight manipulations of the propagating phonons. The ability to route short, 100 ns, pulses enables new functionality, for instance to catch an acoustic phonon between two qubits and then release it in a controlled direction.
We have observed the Autler-Townes doublet in a superconducting AI/AIO sub(X)/AI transmon qubit that acts as an artificial atom embedded in a three-dimensional Cu microwave cavity at a temperature of ...22 mK. Using pulsed microwave spectroscopy, the three lowest transmon levels are isolated, eliminating unwanted effects of higher qubit modes and cavity modes. The long coherence time (~ 40 mu s) of the transmon enables us to observe a clear Autler-Townes splitting at drive amplitudes much smaller than the transmon level anharmonicity (177 MHz). Three-level density matrix simulations with no free parameters provide excellent fits to the data. At maximum separation, the fidelity of a dark state achieved in this experiment is estimated to be 99.6%- 99.9%.
Atomic three-level Lambda1 systems dressed by two coherent electromagnetic elds can exhibit coherent population trapping and electromagnetically induced transparency (EIT) due to quantum ...interference. By addressing the combined qubitcavity states of a superconducting transmon qubit in a three-dimensional copper cavity with two microwave drives we establish an eective Lambda1 system, two legs of which are dened by a dipole transition and a two-photon transition.
Substantial efforts have been devoted to the promotion of Zero Tillage as part of a Conservation Agriculture based Sustainable Intensification agenda in the Eastern Gangetic Plains of South Asia, yet ...there is no clear understanding of the gendered implications of the required change in weed management practices from tillage to herbicides. Other geographies such as in Sub-Saharan Africa have shown evidence that transitioning to Zero Tillage may have unbalanced gendered implications that burden women with additional tasks or lead to lessening agency. To address this, a targeted in-depth study with both spouses was implemented in 24 households across Bangladesh, India and Nepal over a period of 5 weeks during crop establishment to understand the perceptions, responsibilities, and knowledge of household spouses who have adopted Zero Tillage systems. This data is used to compare their weeding responsibilities and knowledge between their Pre- and post- Zero Tillage uptake. Findings indicate that the switch to Zero Tillage contributed to substantial time savings in India and Nepal and did not lead to any reallocation or increased burden of roles and responsibilities to women in any of the surveyed localities, while knowledge on weed management practices were balanced among spouses. This research suggests that the gendered experiences of users of Zero Tillage systems and subsequent use of herbicides in investigated locations may differ from Zero Tillage user experience in other geographies, in that Zero Tillage use did not reinforce or deepen existing inequalities within households. This highlights that Zero Tillage may provide an inclusive agricultural development pathway in the Eastern Gangetic Plains of South Asia.
We present results on a circuit QED experiment in which a separate transmission line is used to address a quasilumped element superconducting microwave resonator which is in turn coupled to an ...Al/AlO(x)/Al Cooper-pair box charge qubit. With our device, we find a strong correlation between the lifetime of the qubit and the inverse of the coupling between the qubit and the transmission line. At the smallest coupling we measured, the lifetime of the Cooper-pair box was T₁=200 μs, which represents more than a twentyfold improvement in the lifetime of the Cooper-pair box compared with previous results. These results imply that the loss tangent in the AlO(x) junction barrier must be less than about 4×10⁻⁸ at 4.5 GHz, about 4 orders of magnitude less than reported in larger area Al/AlO(x)/Al tunnel junctions.
Conservation agriculture-based sustainable intensification (CASI) is gaining prominence as an agricultural pathway to poverty reduction and enhancement of sustainable food systems among government ...and development actors in the Eastern Gangetic Plains (EGP) of South Asia. Despite substantial investment in research and extension programs and a growing understanding of the agronomic, economic and labor-saving benefits of CASI, uptake remains limited. This study explores farmer experiences and perspectives to establish why farmers choose not to implement CASI systems despite a strong body of recent scientific evidence establishing the benefits of them doing so. Through thematic coding of semi-structured interviews, key constraints are identified, which establishes a narrative that current households' resources are insufficient to enable practice change, alongside limited supporting structures for resource supplementation. Such issues create a dependency on subsidies and outside support, a situation that is likely to impact any farming system change given the low-risk profiles of farmers and their limited resource base. This paper hence sets out broad implications for creating change in smallholder farming systems in order to promote the adoption of sustainable agricultural technologies in resource-poor smallholder contexts, especially with regard to breaking the profound poverty cycles that smallholder farmers find themselves in and which are unlikely to be broken by the current set of technologies promoted to them.
The inhibitory receptor CTLA4 has a key role in peripheral tolerance of T cells for both normal and tumor-associated antigens. Murine experiments suggested that blockade of CTLA4 might have antitumor ...activity and a clinical experience with the blocking antibody ipilimumab in patients with metastatic melanoma did show durable tumor regressions in some patients. Therefore, a phase II study of ipilimumab was conducted in patients with metastatic renal cell cancer with a primary end point of response by Response Evaluation Criteria in Solid Tumors (RECIST) criteria. Two sequential cohorts received either 3 mg/kg followed by 1 mg/kg or all doses at 3 mg/kg every 3 weeks (with no intention of comparing cohort response rates). Major toxicities were enteritis and endocrine deficiencies of presumed autoimmune origin. One of 21 patients receiving the lower dose had a partial response. Five of 40 patients at the higher dose had partial responses (95% confidence interval for cohort response rate 4% to 27%) and responses were seen in patients who had previously not responded to IL-2. Thirty-three percent of patients experienced a grade III or IV immune-mediated toxicity. There was a highly significant association between autoimmune events (AEs) and tumor regression (response rate=30% with AE, 0% without AE). CTLA4 blockade with ipilimumab induces cancer regression in some patients with metastatic clear cell renal cancer, even if they have not responded to other immunotherapies. These regressions are highly associated with other immune-mediated events of presumed autoimmune origin by mechanisms as yet undefined.
▶ Calibration curves for Cr in nickel samples using the internal standardization method. ▶ Effect of slopes and regression coefficients of the linear calibration curves investigated. ▶ Optimum ...analytical predictive capability of the LIBS system discussed.
This work reports on the quantitative elemental analysis of nickel alloys using laser-induced breakdown spectroscopy (LIBS) in air at atmospheric pressure. The LIBS plasma is generated using a Q-switched ultraviolet Nd:YAG laser, which evolves with time. The LIBS spectra of three samples with known composition are recorded at five detector gate delays. Employing the internal standardization method, the calibration curves for Cr present in the samples are produced. The Cr concentration in the samples is determined using the generated linear calibration curves having varying slopes and regression coefficients at different delays. The effect of slopes and regression coefficients of the linear calibration curves on the analytical predictive capability of the LIBS system is studied through the correlation of the LIBS determined concentration of Cr with its known value. The analytical predictive capability of the LIBS system is noted to be the best when the calibration-based analysis is performed at an appropriate delay (2000ns in the present experiment) where the linear calibration curve has both the regression coefficient and the slope close to the ideal value.
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