271 research outputs found
Dynamics of the electric current in an ideal electron gas: A sound mode inside the quasiparticles.
Theoretical Physic
Classical approach in quantum physics
The application of a classical approach to various quantum problems - the
secular perturbation approach to quantization of a hydrogen atom in external
fields and a helium atom, the adiabatic switching method for calculation of a
semiclassical spectrum of hydrogen atom in crossed electric and magnetic
fields, a spontaneous decay of excited states of a hydrogen atom, Gutzwiller's
approach to Stark problem, long-lived excited states of a helium atom recently
discovered with the help of Poincar section, inelastic
transitions in slow and fast electron-atom and ion-atom collisions - is
reviewed. Further, a classical representation in quantum theory is discussed.
In this representation the quantum states are treating as an ensemble of
classical states. This approach opens the way to an accurate description of the
initial and final states in classical trajectory Monte Carlo (CTMC) method and
a purely classical explanation of tunneling phenomenon. The general aspects of
the structure of the semiclassical series such as renormgroup symmetry,
criterion of accuracy and so on are reviewed as well. In conclusion, the
relation between quantum theory, classical physics and measurement is
discussed.Comment: This review paper was rejected from J.Phys.A with referee's comment
"The author has made many worthwhile contributions to semiclassical physics,
but this article does not meet the standard for a topical review"
Ionization of hydrogen and hydrogenic ions by antiprotons
Presented here is a description of the ionization of hydrogen and hydrogenic
ions by antiproton-impact, based on very large scale numerical solutions of the
time-dependent Schr\"odinger equation in three spatial dimensions and on
analysis of the topology of the electronic eigenenergy surfaces in the plane of
complex internuclear distance. Comparison is made with other theories and very
recent measurements.Comment: RevTex document, 11 pages, 4 Postscript figures are available from
the authors, in press Phys. Rev. Let
Holographic RG flow of the shear viscosity to entropy density ratio in strongly coupled anisotropic plasma
We study holographic RG flow of the shear viscosity tensor of anisotropic,
strongly coupled N=4 super-Yang-Mills plasma by using its type IIB supergravity
dual in anisotropic bulk spacetime. We find that the shear viscosity tensor has
three independent components in the anisotropic bulk spacetime away from the
boundary, and one of the components has a non-trivial RG flow while the other
two have a trivial one. For the component of the shear viscosity tensor with
non-trivial RG flow, we derive its RG flow equation, and solve the equation
analytically to second order in the anisotropy parameter 'a'. We derive the RG
equation using the equation of motion, holographic Wilsonian RG method, and
Kubo's formula. All methods give the same result. Solving the equation, we find
that the ratio of the component of the shear viscosity tensor to entropy
density 'eta/s' flows from above '1/4pi' at the horizon (IR) to below '1/4pi'
at the boundary (UV) where it violates the holographic shear viscosity
(Kovtun-Son-Starinets) bound and where it agrees with the other longitudinal
component.Comment: 17 pages, 2 figures, slight change on the title, more background
material added, references added, accepted for publication in JHE
Procedures of sensors deployment methodology on physical supports/platforms
The aim of task 2.3 is to define specific platform characteristics and identify deployment difficulties in order to determine the adequacy of sensors within specific platforms. In order to obtain the necessary information, two online questionnaires were realized. One questionnaire was created for sensor developers and one for those partners that will test the sensors at sea.
The seven developers in COMMON SENSE have provided information on seven sensors: two for underwater noise – CEFAS and IOPAN; two for microplastics – IDRONAUT and LEITAT; one for an innovative piro and piezo resistive polymeric temperature and pressure – CSIC; one for heavy metal – CSIC; one for eutrophication sensor – DCU. Outside the scope of the questionnaire, FTM has proposed three sensors of which two for oil spill and one for heavy metals, realized in the framework of a previous EU project but that can be improved and tested with several platforms.
This information is anyway incomplete because in most cases for the novel sensors which will be developed over the course of COMMON SENSE, the sensors cannot be clearly designed yet as the project only started a few months ago - and, consequently, technical characteristics cannot actually be perfectly defined. This produces some lag in the acquired information that will be solved in the near future.
In the other questionnaire, partners-testers have provided information on eleven platforms. Outside the questionnaire, IOPAN has described two more platforms, one of which is a motorboat not previously listed in the DoW, and they have informed us that the oceanographic buoy in Gdansk Bay is not actually available. This is valid also for platforms from other partners where there were only preliminary contacts like for example for Aqualog and OBSEA Underwater observatory.
In the following months, new information will be provided and questionnaires information updated. Then important characteristics have to be considered such as maintenance, energy autonomy, data transfer/storage and dimension of the sensors that are actually missing.
Further updates of this report are therefore necessary in order to individuate the most suitable platforms to test each kind of sensor and then used at the end of 2014 when WP9 (Testing activities) will start.
Objectives and rationale
The objective of deliverable 2.2 is the definition of the characteristics and procedures of sensors deployment methodology on physical supports/platforms, possible needs and characteristics of the available platform.
This is preparatory for the activities in other WPs and tasks:
- for task 2.2 (New generation technologies), that will provide cost-effective sensors for large scale production through Deliverable 2.1 [month 10];
- for task 2.5 (Monitoring strategy) where sensitivity and stress tests of new sensors will be designed in order to establish confidence limits under different situations and certify the performance of the new instruments [Deliverable 2.5 at month 16].
- for WP9 (Field testing) starting at month 12 (October 2014) when the deployment of new sensors will be drawn and then realized
Ionization via Chaos Assisted Tunneling
A simple example of quantum transport in a classically chaotic system is
studied. It consists in a single state lying on a regular island (a stable
primary resonance island) which may tunnel into a chaotic sea and further
escape to infinity via chaotic diffusion. The specific system is realistic : it
is the hydrogen atom exposed to either linearly or circularly polarized
microwaves. We show that the combination of tunneling followed by chaotic
diffusion leads to peculiar statistical fluctuation properties of the energy
and the ionization rate, especially to enhanced fluctuations compared to the
purely chaotic case. An appropriate random matrix model, whose predictions are
analytically derived, describes accurately these statistical properties.Comment: 30 pages, 11 figures, RevTeX and postscript, Physical Review E in
pres
Doping the holographic Mott insulator
Mott insulators form because of strong electron repulsions, being at the
heart of strongly correlated electron physics. Conventionally these are
understood as classical "traffic jams" of electrons described by a short-ranged
entangled product ground state. Exploiting the holographic duality, which maps
the physics of densely entangled matter onto gravitational black hole physics,
we show how Mott-insulators can be constructed departing from entangled
non-Fermi liquid metallic states, such as the strange metals found in cuprate
superconductors. These "entangled Mott insulators" have traits in common with
the "classical" Mott insulators, such as the formation of Mott gap in the
optical conductivity, super-exchange-like interactions, and form "stripes" when
doped. They also exhibit new properties: the ordering wave vectors are detached
from the number of electrons in the unit cell, and the DC resistivity diverges
algebraically instead of exponentially as function of temperature. These
results may shed light on the mysterious ordering phenomena observed in
underdoped cuprates.Comment: 27 pages, 9 figures. Accepted in Nature Physic
Analysis of relevant technical issues and deficiencies of the existing sensors and related initiatives currently set and working in marine environment. New generation technologies for cost-effective sensors
The last decade has seen significant growth in the field of sensor networks, which are currently collecting large amounts of environmental data. This data needs to be collected, processed, stored and made available for analysis and interpretation in a manner which is meaningful and accessible to end users and stakeholders with a range of requirements, including government agencies, environmental agencies, the research community, industry users and the public.
The COMMONSENSE project aims to develop and provide cost-effective, multi-functional innovative sensors to perform reliable in-situ measurements in the marine environment. The sensors will be easily usable across several platforms, and will focus on key parameters including eutrophication, heavy metal contaminants, marine litter (microplastics) and underwater noise descriptors of the MSFD.
The aims of Tasks 2.1 and 2.2 which comprise the work of this deliverable are:
• To obtain a comprehensive understanding and an up-to-date state of the art of existing sensors.
• To provide a working basis on “new generation” technologies in order to develop cost-effective sensors suitable for large-scale production.
This deliverable will consist of an analysis of state-of-the-art solutions for the different sensors and data platforms related with COMMONSENSE project. An analysis of relevant technical issues and deficiencies of existing sensors and related initiatives currently set and working in marine environment will be performed. Existing solutions will be studied to determine the main limitations to be considered during novel sensor developments in further WP’s.
Objectives & Rationale
The objectives of deliverable 2.1 are:
• To create a solid and robust basis for finding cheaper and innovative ways of gathering data.
This is preparatory for the activities in other WPs:
for WP4 (Transversal Sensor development and Sensor Integration),
for WP(5-8) (Novel Sensors) to develop cost-effective sensors suitable for large-scale production, reducing costs of data collection (compared to commercially available sensors), increasing data access availability
for WP9 (Field testing) when the deployment of new sensors will be drawn and then realized
Protocols for the field testing
The COMMON SENSE project has been designed and planned in order to meet the general and specific scientific and technical objectives mentioned in its Description of Work (page 77).
In an overall strategy of the work plan, work packages (11) can be grouped into 3 key phases: (1) RD basis for cost-effective sensor development, (2) Sensor development, sensor web platform and integration, and (3) Field testing. In the first two phases WP1 and WP2 partners have provided a general understanding and integrated basis for a cost effective sensors development. Within the following WPs 4 to 8 the new sensors are created and integrated into different identified platforms. During the third phase 3, characterized by WP9, partners will deploy precompetitive prototypes at chosen platforms (e.g. research vessels, oil platforms, buoys and submerged moorings, ocean racing yachts, drifting buoys). Starting from August 2015 (month 22; task 9.2), these platforms will allow the partnership to test the adaptability and performance of the in-situ sensors and verify if the transmission of data is properly made, correcting deviations.
In task 9.1 all stakeholders identified in WP2, and other relevant agents, have been contacted in order to close a coordinated agenda for the field testing phase for each of the platforms. Field testing procedures (WP2) and deployment specificities, defined during sensor development in WPs 4 to 8, are closely studied by all stakeholders involved in field testing activities in order for everyone to know their role, how to proceed and to provide themselves with the necessary material and equipment (e.g. transport of instruments). All this information will provide the basis for designing and coordinating field testing activities.
Type and characteristics of the system (vessel or mooring, surface or deep, open sea or coastal area, duration, etc.), used for the field testing activities, are planned comprising the indicators included in the above-mentioned descriptors, taking into account that they must of interest for eutrophication, concentration of contaminants, marine litter and underwater noise.
In order to obtain the necessary information, two tables were realized starting from the information acquired for D2.2 delivered in June 2014. One table was created for sensor developers and one for those partners that will test the sensors at sea.
The six developers in COMMON SENSE have provided information on the seven sensors: CEFAS and IOPAN for underwater noise; IDRONAUT and LEITAT for microplastics; CSIC for an innovative piro and piezo resistive polymeric temperature and pressure and for heavy metal; DCU for the eutrophication sensor.
This information is anyway incomplete because in most cases the novel sensors are still far to be ready and will be developed over the course of COMMON SENSE. So the sensors cannot be clearly designed yet and, consequently, technical characteristics cannot still be perfectly defined. This produces some lag in the acquired information and, consequently, in the planning of their testing on specific platforms that will be solved in the near future.
In the table for Testers, partners have provided information on fifteen available platforms. Specific answers have been given on number and type of sensors on each platforms, their availability and technical characteristics, compatibility issues and, very important when new sensors are tested, comparative measurements to be implemented to verify them.
Finally IOPAN has described two more platforms, a motorboat not listed in the DoW, but already introduced in D2.2, and their oceanographic buoy in the Gdansk Bay that was previously unavailable. The same availability now is present for the OBSEA Underwater observatory from CSIC, while their Aqualog undulating mooring is still not ready for use.
In the following months, new information on sensors and platforms will be provided and the planning of testing activities will improve. Further updates of this report will be therefore necessary in order to individuate the most suitable platforms to test each kind of sensor.
Objectives and rationale
The objective of deliverable 9.1 is the definition of field testing procedures (WP2), the study of deployment specificities during sensor development work packages (from WP4 to WP8) and the preparation of protocols. This with the participation of all stakeholders involved in field testing activities in order for everyone to know their role, how to proceed and to provide themselves with the necessary material and equipment
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