273 research outputs found
Decoherence spectroscopy with individual two-level tunneling defects
Recent progress with microfabricated quantum devices has revealed that an
ubiquitous source of noise originates in tunneling material defects that give
rise to a sparse bath of parasitic two-level systems (TLSs). For
superconducting qubits, TLSs residing on electrode surfaces and in tunnel
junctions account for a major part of decoherence and thus pose a serious
roadblock to the realization of solid-state quantum processors.
Here, we utilize a superconducting qubit to explore the quantum state
evolution of coherently operated TLSs in order to shed new light on their
individual properties and environmental interactions. We identify a
frequency-dependence of TLS energy relaxation rates that can be explained by a
coupling to phononic modes rather than by anticipated mutual TLS interactions.
Most investigated TLSs are found to be free of pure dephasing at their energy
degeneracy points, around which their Ramsey and spin-echo dephasing rates
scale linearly and quadratically with asymmetry energy, respectively. We
provide an explanation based on the standard tunneling model, and identify
interaction with incoherent low-frequency (thermal) TLSs as the major mechanism
of the pure dephasing in coherent high-frequency TLS.Comment: 6 pages, 3 figures, supplementary material availabl
Quantum simulation of the spin-boson model with a microwave circuit
We consider superconducting circuits for the purpose of simulating the
spin-boson model. The spin-boson model consists of a single two-level system
coupled to bosonic modes. In most cases, the model is considered in a limit
where the bosonic modes are sufficiently dense to form a continuous spectral
bath. A very well known case is the ohmic bath, where the density of states
grows linearly with the frequency. In the limit of weak coupling or large
temperature, this problem can be solved numerically. If the coupling is strong,
the bosonic modes can become sufficiently excited to make a classical
simulation impossible. Here, we discuss how a quantum simulation of this
problem can be performed by coupling a superconducting qubit to a set of
microwave resonators. We demonstrate a possible implementation of a continuous
spectral bath with individual bath resonators coupling strongly to the qubit.
Applying a microwave drive scheme potentially allows us to access the
strong-coupling regime of the spin-boson model. We discuss how the resulting
spin relaxation dynamics with different initialization conditions can be probed
by standard qubit-readout techniques from circuit quantum electrodynamics.Comment: 23 pages, 10 figure
Momentum dependence of the excitons in pentacene
We have carried out electron energy-loss investigations of the lowest singlet
excitons in pentacene at 20 K. Our studies allow to determine the full exciton
band structure in the a*,b* reciprocal lattice plane. The lowest singlet
exciton can move coherently within this plane, and the resulting exciton
dispersion is highly anisotropic. The analysis of the energetically following
(satellite) features indicates a strong admixture of charge transfer
excitations to the exciton wave function.Comment: 13 pages, 4 figure
Using a multi-lens framework for landscape decisions
1. Landscape decisions are multi-faceted. Framing landscape decision-making as a governance process that requires a collective approach can encourage key stakeholders to come together to co-inform a discussion about their priorities and what constitutes good governance, leading to more holistic landscape decisions.
2. In this paper, we recognise that a suite of complementary and multi-dimensional approaches are in practice used to inform and evaluate land use decisions. We have called these approaches ‘lenses’ because they each provide a different perspective on the same problem. The four lenses are: i) Power and Market Gain, ii) Ecosystem Services, iii), Place-based Identity and iv) Ecocentric. Each brings a different set of evidence and viewpoints (narrative, qualitative and experiential, as well as quantitative metrics such as monetary) to the decision-making process and can potentially reveal problems and solutions that others do not.
3. Considering all lenses together allows dialogue to take place which can reveal the true complexities of landscape decision-making and can facilitate more effective and more holistic decisions. Employing the lenses requires governance structures that give equal weight to all lenses, enable dialogue and coexistence between top down and bottom-up approaches, and permit adaptation to local and granular place-specifics rather than developing “one-size-fits-all” solutions.
4. We propose that formalising the process of balancing all the lenses requires public participation, and that a lens approach should be used to support landscape decisions alongside a checklist that facilitates transparency in the conversation, showing how all evidence has been considered and critically assessed
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A New Methodology for Reducing Carbon Emissions Using Multi-Renewable Energy Systems and Artificial Intelligence
Data availability: The data that has been used is confidential.Microgrid cost management is a significant difficulty because the energy generated by microgrids is typically derived from a variety of renewable and non-renewable sources. Furthermore, in order to meet the requirements of freed energy markets and secure load demand, a link between the microgrid and the national grid is always preferred. For all of these reasons, in order to minimize operating expenses, it is imperative to design a smart energy management unit to regulate various energy resources inside the microgrid. In this study, a smart unit idea for multi-source microgrid operation and cost management is presented. The proposed unit utilizes the Improved Artificial Rabbits Optimization Algorithm (IAROA) which is used to optimize the cost of operation based on current load demand, energy prices and generation capacities. Also, a comparison between the optimization outcomes obtained results is implemented using Honey Badger Algorithm (HBA), and Whale Optimization Algorithm (WOA). The results prove the applicability and feasibility of the proposed method for the demand management system in SMG. The price after applying HBA is 6244.5783 (ID). But after applying the Whale Optimization Algorithm, the cost is found 4283.9755 (ID), and after applying the Artificial Rabbits Optimization Algorithm, the cost is found 1227.4482 (ID). By comparing the proposed method with conventional method, the whale optimization algorithm saved 31.396% per day, and the proposed artificial rabbit's optimization algorithm saved 80.3437% per day. From the obtained results the proposed algorithm gives superior performance.The research has been partially supported by the Faculty of Informatics and Management UHK excellence project “Methodological perspectives on modelling and simulation of hard and soft systems”
Tsunami-Related Data: A Review of Available Repositories Used in Scientific Literature
Various organizations and institutions store large volumes of tsunami-related data, whose
availability and quality should benefit society, as it improves decision making before the tsunami
occurrence, during the tsunami impact, and when coping with the aftermath. However, the existing
digital ecosystem surrounding tsunami research prevents us from extracting the maximum benefit
from our research investments. The main objective of this study is to explore the field of data
repositories providing secondary data associated with tsunami research and analyze the current
situation. We analyze the mutual interconnections of references in scientific studies published in the
Web of Science database, governmental bodies, commercial organizations, and research agencies. A
set of criteria was used to evaluate content and searchability. We identified 60 data repositories with
records used in tsunami research. The heterogeneity of data formats, deactivated or nonfunctional
web pages, the generality of data repositories, or poor dataset arrangement represent the most
significant weak points. We outline the potential contribution of ontology engineering as an example
of computer science methods that enable improvements in tsunami-related data management
Decoherence spectroscopy with individual two-level tunneling defects
Recent progress with microfabricated quantum devices has revealed that an ubiquitous source of noise originates in tunneling material defects that give rise to a sparse bath of parasitic two-level systems (TLSs). For superconducting qubits, TLSs residing on electrode surfaces and in tunnel junctions account for a major part of decoherence and thus pose a serious roadblock to the realization of solid-state quantum processors. Here, we utilize a superconducting qubit to explore the quantum state evolution of coherently operated TLSs in order to shed new light on their individual properties and environmental interactions. We identify a frequency-dependence of TLS energy relaxation rates that can be explained by a coupling to phononic modes rather than by anticipated mutual TLS interactions. Most investigated TLSs are found to be free of pure dephasing at their energy degeneracy points, around which their Ramsey and spin-echo dephasing rates scale linearly and quadratically with asymmetry energy, respectively. We provide an explanation based on the standard tunneling model, and identify interaction with incoherent low-frequency (thermal) TLSs as the major mechanism of the pure dephasing in coherent high-frequency TLS
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A novel efficient energy optimization in smart urban buildings based on optimal demand side management
Data availability:
The data used for this research and prepatation of this article can be accessed from Brunel University of London repository at: https://doi.org/10.17633/rd.brunel.26049436.v1.Increasing electrical energy consumption during peak hours leads to increased electrical energy losses and the spread of environmental pollution. For this reason, demand-side management programs have been introduced to reduce consumption during peak hours. This study proposes an efficient energy optimization in Smart Urban Buildings (SUBs) based on Improved Sine Cosine Algorithm (ISCA) that uses the load-shifting technique for demand-side management as a way to improve the energy consumption patterns of a SUBs. The proposed system's goal is to optimize the energy of SUBs appliances in order to effectively regulate load demand, with the end result being a reduction in the peak to average ratio (PAR) and a consequent minimization of electricity costs. This is accomplished while also keeping user comfort as a priority. The proposed system is evaluated by comparing it with the Grasshopper Optimization Algorithm (GOA) and unscheduled cases. Without applying an optimization algorithm, the total electricity cost, carbon emission, PAR and waiting time are equal to 1703.576 ID, 34.16664 (kW), and 413.5864s respectively for RTP. While, after applying GOA, the total electricity cost, carbon emission, PAR and waiting time are improved to 1469.72 ID, 21.17 (kW), and 355.772s respectively for RTP. While, after applying the ISCA Improves the total electricity cost, PAR, and waiting time by 1206.748 ID, 16.5648 (kW), and 268.525384s respectively. Where after applying GOA, the total electricity cost, PAR, and waiting time are improved to 13.72 %, 38.00 %, and 13.97 % respectively. And after applying proposed method, the total electricity cost, PAR, and waiting time are improved to 29.16 %, 51.51 %, and 35.07 % respectively. According to the results, the created ISCA algorithm performed better than the unscheduled case and GOA scheduling situations in terms of the stated objectives and was advantageous to both utilities and consumers. Furthermore, this study has presented a novel two-stage stochastic model based on Moth-Flame Optimization Algorithm (MFOA) for the co-optimization of energy scheduling and capacity planning for systems of energy storage that would be incorporated to grid connected smart urban buildings.The research has been partially supported by the Faculty of Informatics and Management UHK excellence project “Methodological perspectives on modeling and simulation of hard and soft systems”
The Australian and New Zealand Society for Sarcopenia and Frailty Research (ANZSSFR) Sarcopenia Diagnosis and Management Task Force: Findings from the consumer Delphi process
OnlinePublObjectives: To develop guidelines, informed by health-care consumer values and preferences, for sarcopenia prevention, assessment and management for use by clinicians and researchers in Australia and New Zealand. Methods: A three-phase Consumer Expert Delphi process was undertaken between July 2020 and August 2021. Consumer experts included adults with lived experience of sarcopenia or health-care utilisation. Phase 1 involved a structured meeting of the Australian and New Zealand Society for Sarcopenia and Frailty Research (ANZSSFR) Sarcopenia Diagnosis and Management Task Force and consumer representatives from which the Phase 2 survey was developed. In Phase 2, consumers from Australia and New Zealand were surveyed online with opinions sought on sarcopenia outcome priorities, consultation preferences and interventions. Findings were confirmed and disseminated in Phase 3. Descriptive statistical analyses were performed. Results: Twenty-four consumers (mean±standard deviation age 67.5 ±12.8 years, 18 women) participated in Phase 2. Ten (42%) identified as being interested in sarcopenia, 7 (29%) were health-care consumers and 6 (25%) self-reported having/believing they have sarcopenia. Consumers identified physical performance, living circumstances, morale, quality of life and social connectedness as the most important outcomes related to sarcopenia. Consumers either had no preference (46%) or preferred their doctor (40%) to diagnose sarcopenia and preferred to undergo assessments at least yearly (54%). For prevention and treatment, 46% of consumers preferred resistance exercise, 2–3 times per week (54%). Conclusions: Consumer preferences reported in this study can inform the implementation of sarcopenia guidelines into clinical practice at local, state and national levels across Australia and New Zealand.Jesse Zanke ... Elsa Dent ... Renuka Visvanathan ... Solomon Yu ... et al
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