A scalable helium gas cooling system for trapped-ion applications

Microfabricated ion-trap devices offer a promising pathway towards scalable quantum computing. Research efforts have begun to focus on the engineering challenges associated with developing large-scale ion-trap arrays and networks. However, increasing the size of the array and integrating on-chip electronics can drastically increase the power dissipation within the ion-trap chips. This leads to an increase in the operating temperature of the ion-trap and limits the device performance. Therefore, effective thermal management is an essential consideration for any large-scale architecture. Presented here is the development of a modular cooling system designed for use with multiple ion-trapping experiments simultaneously. The system includes an extensible cryostat that permits scaling of the cooling power to meet the demands of a large network. Following experimental testing on two independent ion-trap experiments, the cooling system is expected to deliver a net cooling power of 111 W at ∼70 K to up to four experiments. The cooling system is a step towards meeting the practical challenges of operating large-scale quantum computers with many qubits

A high-fidelity quantum matter-link between ion-trap microchip modules

System scalability is fundamental for large-scale quantum computers (QCs) and is being pursued over a variety of hardware platforms. For QCs based on trapped ions, architectures such as the quantum charge-coupled device (QCCD) are used to scale the number of qubits on a single device. However, the number of ions that can be hosted on a single quantum computing module is limited by the size of the chip being used. Therefore, a modular approach is of critical importance and requires quantum connections between individual modules. Here, we present the demonstration of a quantum matter-link in which ion qubits are transferred between adjacent QC modules. Ion transport between adjacent modules is realised at a rate of 2424 s−1 and with an infidelity associated with ion loss during transport below 7 × 10−8. Furthermore, we show that the link does not measurably impact the phase coherence of the qubit. The quantum matter-link constitutes a practical mechanism for the interconnection of QCCD devices. Our work will facilitate the implementation of modular QCs capable of fault-tolerant utility-scale quantum computation

T2K measurements of muon neutrino and antineutrino disappearance using 3.13×1021 protons on target

We report measurements by the T2K experiment of the parameters θ23 and Δm322, which govern the disappearance of muon neutrinos and antineutrinos in the three-flavor PMNS neutrino oscillation model at T2K\u27s neutrino energy and propagation distance. Utilizing the ability of the experiment to run with either a mainly neutrino or a mainly antineutrino beam, muon-like events from each beam mode are used to measure these parameters separately for neutrino and antineutrino oscillations. Data taken from 1.49×1021 protons on target (POT) in neutrino mode and 1.64×1021 POT in antineutrino mode are used. The best-fit values obtained by T2K were sin2(θ23)=0.51-0.07+0.06(0.43-0.05+0.21) and Δm322=2.47-0.09+0.08(2.50-0.13+0.18)×10-3 eV2/c4 for neutrinos (antineutrinos). No significant differences between the values of the parameters describing the disappearance of muon neutrinos and antineutrinos were observed. An analysis using an effective two-flavor neutrino oscillation model where the sine of the mixing angle is allowed to take nonphysical values larger than 1 is also performed to check the consistency of our data with the three-flavor model. Our data were found to be consistent with a physical value for the mixing angle

Improved constraints on neutrino mixing from the T2K experiment with 3.13×1021 protons on target

The T2K experiment reports updated measurements of neutrino and antineutrino oscillations using both appearance and disappearance channels. This result comes from an exposure of 14.9(16.4)×1020 protons on target in neutrino (antineutrino) mode. Significant improvements have been made to the neutrino interaction model and far detector reconstruction. An extensive set of simulated data studies have also been performed to quantify the effect interaction model uncertainties have on the T2K oscillation parameter sensitivity. T2K performs multiple oscillation analyses that present both frequentist and Bayesian intervals for the Pontecorvo-Maki-Nakagawa-Sakata parameters. For fits including a constraint on sin2θ13 from reactor data and assuming normal mass ordering T2K measures sin2θ23=0.53-0.04+0.03 and Δm322=(2.45±0.07)×10-3 eV2 c-4. The Bayesian analyses show a weak preference for normal mass ordering (89% posterior probability) and the upper sin2θ23 octant (80% posterior probability), with a uniform prior probability assumed in both cases. The T2K data exclude CP conservation in neutrino oscillations at the 2σ level

A pilot study on mindfulness based stress reduction for smokers

BACKGROUND: Mindfulness means paying attention in the present moment, non-judgmentally, without commentary or decision-making. We report results of a pilot study designed to test the feasibility of using Mindfulness Based Stress Reduction (MBSR) (with minor modifications) as a smoking intervention. METHODS: MBSR instructors provided instructions in mindfulness in eight weekly group sessions. Subjects attempted smoking cessation during week seven without pharmacotherapy. Smoking abstinence was tested six weeks after the smoking quit day with carbon monoxide breath test and 7-day smoking calendars. Questionnaires were administered to evaluate changes in stress and affective distress. RESULTS: 18 subjects enrolled in the intervention with an average smoking history of 19.9 cigarettes per day for 26.4 years. At the 6-week post-quit visit, 10 of 18 subjects (56%) achieved biologically confirmed 7-day point-prevalent smoking abstinence. Compliance with meditation was positively associated with smoking abstinence and decreases in stress and affective distress. DISCUSSIONS AND CONCLUSION: The results of this study suggest that mindfulness training may show promise for smoking cessation and warrants additional study in a larger comparative trial

Measurements of and + charged-current cross-sections without detected pions or protons on water and hydrocarbon at a mean anti-neutrino energy of 0.86 GeV

We report measurements of the flux-integrated and + charged-current cross-sections on water and hydrocarbon targets using the T2K anti-neutrino beam with a mean beam energy of 0.86 GeV. The signal is defined as the (anti-)neutrino charged-current interaction with one induced and no detected charged pion or proton. These measurements are performed using a new WAGASCI module recently added to the T2K setup in combination with the INGRID Proton Module. The phase space of muons is restricted to the high-detection efficiency region, 400 and 30 , in the laboratory frame. An absence of pions and protons in the detectable phase spaces of 200, 70 and 600, 70 is required. In this paper, both the; cross-sections and +; cross-sections on water and hydrocarbon targets and their ratios are provided by using the D\u27Agostini unfolding method. The results of the integrated ; cross-section measurements over this phase space are ;\sigma{\rm H{2}O}=(1.082\pm0.068(\rm stat.) {+0.145}{-0.128}(\rm syst.)) \times 10 {-39}\,{\rm cm {2} / nucleon};, ;\sigma{\rm CH}=(1.096\pm0.054(\rm stat.) {+0.132}{-0.117}(\rm syst.)) \times 10 {-39}\,{\rm cm {2} / nucleon};, and ;\sigma{\rm H{2}O}/\sigma{\rm CH} = 0.987\pm0.078(\rm stat.) {+0.093}{-0.090}(\rm syst.);. The +; cross-section is ;\sigma{\rm H{2}O} = (1.155\pm0.064(\rm stat.) {+0.148}{-0.129}(\rm syst.)) \times 10 {-39}\,{\rm cm {2} / nucleon};, ;\sigma{\rm CH}=(1.159\pm0.049(\rm stat.) {+0.129}{-0.115}(\rm syst.)) \times 10 {-39}\,{\rm cm {2} / nucleon};, and ;\sigma{\rm H{2}O}/\sigma{\rm CH}=0.996\pm0.069(\rm stat.) {+0.083}{-0.078}(\rm syst.);

Measurements of the νμ\nu_{\mu} and νˉμ\bar{\nu}_{\mu}-induced Coherent Charged Pion Production Cross Sections on 12C^{12}C by the T2K experiment

We report an updated measurement of the $\nu_{\mu}$-induced, and the first measurement of the $\bar{\nu}_{\mu}$-induced coherent charged pion production cross section on $^{12}C$ nuclei in the T2K experiment. This is measured in a restricted region of the final-state phase space for which $p_{\mu,\pi} > 0.2$ GeV, $\cos(\theta_{\mu}) > 0.8$ and $\cos(\theta_{\pi}) > 0.6$, and at a mean (anti)neutrino energy of 0.85 GeV using the T2K near detector. The measured $\nu_{\mu}$ CC coherent pion production flux-averaged cross section on $^{12}C$ is $(2.98 \pm 0.37 (stat.) \pm 0.31 (syst.) \substack{ +0.49 \\ -0.00 } \mathrm{ (Q^2\,model)}) \times 10^{-40}~\mathrm{cm}^{2}$. The new measurement of the $\bar{\nu}_{\mu}$-induced cross section on $^{12}{C}$ is $(3.05 \pm 0.71 (stat.) \pm 0.39 (syst.) \substack{ +0.74 \\ -0.00 } \mathrm{(Q^2\,model)}) \times 10^{-40}~\mathrm{cm}^{2}$. The results are compatible with both the NEUT 5.4.0 Berger-Sehgal (2009) and GENIE 2.8.0 Rein-Sehgal (2007) model predictions

Engaged, but not immersed: Tracking the mediated public connection of Filipino elite migrants in London

While most of the literature highlights the social, economic and cultural aspects of Filipino migration, this study explores its political dimension by focusing on the public connection of Filipino elite migrants in London. Unlike other types of Filipino migrants, such as Americanized balikbayans and ‘low-skilled’ labour migrants, elite migrants are expected to return physically to the homeland as part of their nationalistic duty to ‘lead the nation’. From their interviews and participant observation, the authors discover that overseas scholars indeed maintain a strong interest in homeland political issues through heavy news consumption on the Internet. However, this has also fostered an ambiguous kind of public connection. On the one hand, elite migrants remain engaged with issues that they hope to address on their eventual return, but on the other hand they are not immersed with ‘other’ Filipino people in the diaspora. Their political engagement involves talk and mediated conversations with limited face-to-face collaborations with other migrants. This kind of public connection lends itself to longdistance particularistic communication and a great volume of discussion, but limited and short-term forms of public activity. The authors argue that elite migrants' practices of political engagement are inscribed in continuing socio-historical – and fundamentally classed – divides in Philippine society. Further, rather than enabling cross-class communications and connections, the media are frequently used by elite migrants to maintain political, economic, social and cultural divides

Art Fairs as a Medium for Branding Young and Emerging Artists: The Case of Frieze London

While previous researchers have attempted to explain the uncertain quality of visual arts with reference to branding theory, they have overlooked the role of art fairs. Socio-cultural approaches to branding allow us to explore the function of intermediaries in valuing contemporary arts. This article aims to analyze the role of art fairs in the process of branding young and emerging artists. In particular, a prestigious art fair, Frieze London, serves as an instrumental case study for developing a systematic understanding of art fairs in terms of valuing and branding contemporary art