In current researches on spectrum leasing, Common model and Property-right model are two main approaches to dynamic spectrum sharing. However, Common model does not consider the obligation of Primary System (PS) and i...In current researches on spectrum leasing, Common model and Property-right model are two main approaches to dynamic spectrum sharing. However, Common model does not consider the obligation of Primary System (PS) and is unfair to Secondary System (SS), while the cooperation based on Property-rights model has problems on its feasibility. This paper proposes a novel system model, in which a Cost-Prediction scheme for Spectrum Leasing (CPSL scheme) is designed to forecast the cost that PS would pay for leasing spectrum. Cost Function is introduced as a criterion to evaluate the potential cost of spectrum leasing for PS. The simulation results show that compared with Common model based scheme, CPSL scheme substantially improves the QoS of the delay-sensitive traffic in SS at the cost of a small degradation of PS performance.展开更多
Research indicates that high levels of sedentary behavior(sitting or lying with low energy expenditure) are adversely associated with health. A key factor in improving our understanding of the impact of sedentary beha...Research indicates that high levels of sedentary behavior(sitting or lying with low energy expenditure) are adversely associated with health. A key factor in improving our understanding of the impact of sedentary behavior(and patterns of sedentary time accumulation) on health is the use of objective measurement tools that collect date and time-stamped activity information. One such tool is the activP AL monitor. This thigh-worn device uses accelerometer-derived information about thigh position to determine the start and end of each period spent sitting/lying, standing, and stepping, as well as stepping speed, step counts, and postural transitions. The activP AL is increasingly being used within field-based research for its ability to measure sitting/lying via posture. We summarise key issues to consider when using the activP AL in physical activity and sedentary behavior field-based research with adult populations. It is intended that the findings and discussion points be informative for researchers who are currently using activP AL monitors or are intending to use them. Pre-data collection decisions, monitor preparation and distribution, data collection considerations, and manual and automated data processing possibilities are presented using examples from current literature and experiences from 2 research groups from the UK and Australia.展开更多
Identifying the flow patterns is vital for understanding the complicated physical mechanisms in multiphase flows.For this purpose,electrical capacitance tomography(ECT) technique is considered as a promising visualiza...Identifying the flow patterns is vital for understanding the complicated physical mechanisms in multiphase flows.For this purpose,electrical capacitance tomography(ECT) technique is considered as a promising visualization method for the flow pattern identification,in which image reconstruction algorithms play an important role.In this paper,a generalized dynamic reconstruction model,which integrates ECT measurement information and physical evolution information of the objects of interest,was presented.A generalized objective functional that simultaneously considers the spatial constraints,temporal constraints and dynamic evolution information of the objects of interest was proposed.Numerical simulations and experiments were implemented to evaluate the feasibility and efficiency of the proposed algorithm.For the cases considered in this paper,the proposed algorithm can well reconstruct the flow patterns,and the quality of the reconstructed images is improved,which indicates that the proposed algorithm is competent to reconstruct the flow patterns in the visualization of multiphase flows.展开更多
In Web 2.0 era,the content on a web page is increasingly generated by end users,rather than limited number of administrators.Hence,large number of User Generated Content(UGC) has driven the explosion of content in the...In Web 2.0 era,the content on a web page is increasingly generated by end users,rather than limited number of administrators.Hence,large number of User Generated Content(UGC) has driven the explosion of content in the web.Thanks to UGC,the pattern of web usage has evolved from download dominated way to a hybrid one with both information download and upload.Large number of UGC has unveiled great capacity of information that is unavailable for researchers before,such as individual preferences,social connections,and etc.In this paper,we propose a novel model which studies the UGC in micro-blogging web sites,the largest and fastest information diffusion media online,and evaluate the social influence for an arbitrary individual.Experimental results show that our model outperforms state-of-the-art techniques in social influence evaluation in both the running time and accuracy.展开更多
Glacier length is a key morphological element that has many glaciological applications; however, it is often difficult to determine, especially for glaciers that cover larger spatial areas or those that exhibit freque...Glacier length is a key morphological element that has many glaciological applications; however, it is often difficult to determine, especially for glaciers that cover larger spatial areas or those that exhibit frequent temporal change. In this paper, we describe a new Arc GIS-based method that can derive glacier flow lines for determining glacier length based on digital elevation model and glacier outlines. This method involves(1) extraction of the highest and lowest points on a glacier,(2) calculation of 10-m contour lines on the glacier from 10 m to 100 m height, and(3) connection of the midpoints of each contour line with the highest and the lowest points in order to create a flow line, which is subsequently smoothed. In order to assess the reliability of this method, we tested the algorithm's results against flow lines calculated using field measurements, analysing data from the Chinese Glacier Inventory, and manual interpretation. These data showed that the new automated method is effective in deriving glacier flow lines when contour lines are relatively large; in particular, when they are between 70 m and 100 m. Nonetheless, a key limitation of the algorithm is the requirement to automatically delete repeated and closed curves in the pre-treatment processes. In addition to calculating glacier flow lines for derivation of glacier length, this method also can be used to effectively determine glacier terminus change.展开更多
Karl Marx (1973) scientifically predicted the appearance of some extraordinary tendencies of social development in the second half of the 20th century was given a common name of post-industrial or informational soci...Karl Marx (1973) scientifically predicted the appearance of some extraordinary tendencies of social development in the second half of the 20th century was given a common name of post-industrial or informational society and interpreted as post-bourgeois, post-capitalist, post-business society, and late capitalism. Autonomist Marxism and Perm philosophy school had separately come to a conclusion that all the phenomena noticed by the post-industrial theory could be adequately explained if we consider the historically new form of material labour appearing now. Marx (1973), who predicted this new form, named it automated, scientific, or universal labour. With the appearance of the universal labour, the wealth of the society depends on the universal human powers that help to involve the extensive powers of nature into the production process. Universal labour can not be averaged or measured by the labour time as the abstract labour; it implies high complexity and creativity. Involving increasingly powerful forces of nature and human society, it appears to be the labour of another essence and by its essence, it does not create value.展开更多
In this study, we analyzed the swing motions of more experienced practitioner and new practitioner of iaido players by using tri-axial acceleration sensor and gyro sensor. Iaido is a modern Japanese martial art/sport....In this study, we analyzed the swing motions of more experienced practitioner and new practitioner of iaido players by using tri-axial acceleration sensor and gyro sensor. Iaido is a modern Japanese martial art/sport. In this way, the acceleration and gyro sensor measurement enabled detailed motion information at the installation points to be displayed in a short time, thus making it possible to easily extract the objective problems. Although it was not possible to confirm by the acceleration and angular velocity measurements the detailed motion of the entire body as obtained in the 2D motion analysis with a high-speed camera, it was confirmed that the acceleration and gyro sensor is an evaluation means that can be installed easily and can provide the exercise information in a short time as an objective index.展开更多
The heat parameters, the thermoanemometric flow-meter (TAF) errors and the experimental characteristics have been defined. The results of experiments were conducted with the help of physically-informational models a...The heat parameters, the thermoanemometric flow-meter (TAF) errors and the experimental characteristics have been defined. The results of experiments were conducted with the help of physically-informational models allowing to realize all major thermal methods and their inherent informative options. The metrological evaluation was made and the sensitivity to the consumption of gas and liquid have been defined, their static and dynamic errors, followed by the comparison of costs according to these criteria. The developed method provides accurate measurement of volumetric flow of motor fuel 1.0-1.5% at heater temperature measurement accuracy of 1%.展开更多
Side information (SI) is one of the key issues in distributed video coding (DVC) and affects the compression performance of DVC largely. This paper proposes an SI refinement algorithm, in which the Wyner-Ziv (WZ...Side information (SI) is one of the key issues in distributed video coding (DVC) and affects the compression performance of DVC largely. This paper proposes an SI refinement algorithm, in which the Wyner-Ziv (WZ) frame is split into two parts based on checkerboard pattern, and the two parts are encoded independently but decoded sequentially. In the decoding process, the part 1 is first decoded with the initial SI and partially decoded part (PDP) 1 is used to improve the motion vectors (MVs) and SI of both parts. At the next stage, the part 2 is decoded with the improved SI and PDP 2 is used to further refine MVs of the part 2. Then, SI of both parts are further refined. Simulation results show that the proposed algorithm can improve the peak signal to noise ratio (PSNR) by up to 1.43 dB when compared with traditional DVC codec.展开更多
This study presents the Shannon and Renyi information entropy for both position and momentum space and the Fisher information for the position-dependent mass Schr¨odinger equation with the Frost-Musulin potential...This study presents the Shannon and Renyi information entropy for both position and momentum space and the Fisher information for the position-dependent mass Schr¨odinger equation with the Frost-Musulin potential. The analysis of the quantum mechanical probability has been obtained via the Fisher information. The variance information of this potential is equally computed. This controls both the chemical properties and physical properties of some of the molecular systems. We have observed the behaviour of the Shannon entropy. Renyi entropy, Fisher information and variance with the quantum number n respectively.展开更多
Recently, a genuine six-qubit entangled state Isix) has been proposed [Chen P X, et al. Phys Rev A, 2006, 74: 032324]. This state does not belong to the well-known three types of multipartite entangled states, i.e.,...Recently, a genuine six-qubit entangled state Isix) has been proposed [Chen P X, et al. Phys Rev A, 2006, 74: 032324]. This state does not belong to the well-known three types of multipartite entangled states, i.e., Greenberger-Home-Zeilinger (GHZ) state, W state, and linear cluster state. This state has many potential applications in quantum information processing. We pro- pose a scheme for generating such a genuine six-qubit entangled state for trapped ions in thermal motion. The scheme is insen- sitive to both the initial motional state and heating.展开更多
We present an efficient two-step entanglement concentration protocol(ECP)for three-level atoms trapped in one-sided optical micro-cavities in an arbitrary three-particle less-entangled W state,using the coherent state...We present an efficient two-step entanglement concentration protocol(ECP)for three-level atoms trapped in one-sided optical micro-cavities in an arbitrary three-particle less-entangled W state,using the coherent state input-output process in low-Q cavity quantum electrodynamics system.In each step of the new proposed protocol,one of the three remote users prepares the auxiliary coherent optical pulses to perform cavity input-output process and then utilizes the standard homodyne measurement to discriminate the final outgoing coherent states.When both of the two steps are successful,remote parties can deterministically concentrate the less-entangled W state atoms to a standard maximally entangled W state.Compared with previous ECPs for W state,this protocol has some advantages and can be widely used in current quantum repeater and some quantum information processing tasks.展开更多
The energy budget of the magnetosphere-ionosphere (MI) system during 1998-2008 was examined by using Akasofu's epsilon function. The results showed that 1) the yearly average rate of solar wind energy input into t...The energy budget of the magnetosphere-ionosphere (MI) system during 1998-2008 was examined by using Akasofu's epsilon function. The results showed that 1) the yearly average rate of solar wind energy input into the MI system was 4.51 GGJ (GGJ=1018 J), while the yearly average total dissipation was 4.30 GGJ; 2) the energy partitioning in the ring current and polar region was 56%:44%; 3) the energy input and dissipation processes continuously proceeded both in storm-substorm events and less disturbed intervals, suggesting the significant contribution of slow but long-lasting energy process during the less disturbance periods to the total energy budget. In addition, we found in this study an interesting phenomenon "self-adjustment ability" of the MI system which behaves just like a water reservoir. During solar active years, the input energy is more than the dissipated energy, implying that a portion of the input energy is not immediately released, but is stored in the magnetosphere. On the other hand, during less active years, the dissipated energy is more than the input energy, implying that the previously stored energy makes up for the energy input shortage in this period.展开更多
The dynamic evolution of a multi-level atom in the three-dimensional photonic crystal under an applied magnetic field is investigated.By combining the Zeeman effect with the photonic band gap effect,the dynamic quantu...The dynamic evolution of a multi-level atom in the three-dimensional photonic crystal under an applied magnetic field is investigated.By combining the Zeeman effect with the photonic band gap effect,the dynamic quantum superposition states and steady quantum coherent trapping states of the atom can be flexibly controlled.This paves the way for coherent manipulation of quantum states in the solid-state system,which has important applications in quantum information processing.展开更多
We investigate the dynamics of the precision of the parameter estimation in many driven atoms, each of which interacts with a local structured bosonic reservoir respectively. The evolution of quantum states for single...We investigate the dynamics of the precision of the parameter estimation in many driven atoms, each of which interacts with a local structured bosonic reservoir respectively. The evolution of quantum states for single driven atom is described by the time local quantum master equation. The dynamics of the quantum Fisher information for many entangled atoms is obtained by means of the supreoperator mapping. The estimation limit is superior to the standard quantum limit during a characteristic interval. At a given time, the precision of parameter estimation can be improved to a maximal value if the number of entangled atoms is chosen to be an optimal value. The optimal number of entangled atoms is determined by the dynamical property. The decay of quantum Fisher information is accelerated with the increase of the number of entangled atoms.展开更多
A non-Markovianity measure based on Brukner–Zeilinger invariant information to characterize nonMarkovian effect of open systems undergoing unital dynamical maps is proposed. The method takes advantage of non-increasi...A non-Markovianity measure based on Brukner–Zeilinger invariant information to characterize nonMarkovian effect of open systems undergoing unital dynamical maps is proposed. The method takes advantage of non-increasing property of the Brukner–Zeilinger invariant information under completely positive and trace-preserving unital maps. The simplicity of computing the Brukner–Zeilinger invariant information is the advantage of the proposed measure because of mainly depending on the purity of quantum state. The measure effectively captures the characteristics of non-Markovianity of unital dynamical maps. As some concrete application, we consider two typical non-Markovian noise channels, i.e., the phase damping channel and the random unitary channel to show the sensitivity of the proposed measure. By investigation, we find that the conditions of detecting the non-Markovianity for the phase damping channel are consistent with the results of existing measures for non-Markovianity, i.e., information flow, divisibility and quantum mutual information. However, for the random unitary channel non-Markovian conditions are same to that of the information flow, but is different from that of the divisibility and quantum mutual information.展开更多
We study the quantum Fisher information(QFI) dynamics of the phase parameter in the enlarged cavityreservoir systems at zero temperature under two situations of large N limit and non-Markovian environment,respectively...We study the quantum Fisher information(QFI) dynamics of the phase parameter in the enlarged cavityreservoir systems at zero temperature under two situations of large N limit and non-Markovian environment,respectively.We find an important relation that the total quantities of QFI of the cavity and reservoir are equal to unit during the dynamical evolution.The lost QFI of the cavity transfers to its corresponding reservoir with the same quantities simultaneously.Moreover,we also find that the detuning parameter and non-Markovian effect are two significant factors to affect the preservation of QFI.展开更多
A strong analog classical simulation of general quantum evolution is proposed, which serves as a novel scheme in quantum computation and simulation. The scheme employs the approach of geometric quantum mechanics and q...A strong analog classical simulation of general quantum evolution is proposed, which serves as a novel scheme in quantum computation and simulation. The scheme employs the approach of geometric quantum mechanics and quantum informational technique of quantum tomography, which applies broadly to cases of mixed states, nonunitary evolution, and infinite dimensional systems. The simulation provides an intriguing classical picture to probe quantum phenomena, namely, a coherent quantum dynamics can be viewed as a globally constrained classical Hamiltonian dynamics of a collection of coupled particles or strings. Efficiency analysis reveals a fundamental difference between the locality in real space and locality in Hilbert space, the latter enables efficient strong analog classical simulations. Examples are also studied to highlight the differences and gaps among various simulation methods.展开更多
基金supported by the National High Technology Research and Development Program of China ('863' Program, No.2009AA01Z242)National Natural Science Foundation of China (60972080)
文摘In current researches on spectrum leasing, Common model and Property-right model are two main approaches to dynamic spectrum sharing. However, Common model does not consider the obligation of Primary System (PS) and is unfair to Secondary System (SS), while the cooperation based on Property-rights model has problems on its feasibility. This paper proposes a novel system model, in which a Cost-Prediction scheme for Spectrum Leasing (CPSL scheme) is designed to forecast the cost that PS would pay for leasing spectrum. Cost Function is introduced as a criterion to evaluate the potential cost of spectrum leasing for PS. The simulation results show that compared with Common model based scheme, CPSL scheme substantially improves the QoS of the delay-sensitive traffic in SS at the cost of a small degradation of PS performance.
基金supported by the National Institute for Health Researsch (NIHR) DietLifestyle & Physical Activity Biomedical Research Unit based at University Hospitals of Leicester and Loughborough University+5 种基金the National Institute for Health Research Collaboration for Leadership in Applied Health Research and Care-East Midlands (NIHR CLAHRC- EM)the Leicester Clinical Trials Unitsupported by a National Health and Medical Research Council (NHMRC) Centre for Research Excellence Grant on Sitting Time and Chronic Disease Prevention-Measurement, Mechanisms and Interventions (APP1057608)supported by a Heart Foundation Postdoctoral (PH 12B 7054)NHMRC Career Development (#1086029) Fellowshipsupported by an Australian Research Council Future Fellowship (FTE 100100918)
文摘Research indicates that high levels of sedentary behavior(sitting or lying with low energy expenditure) are adversely associated with health. A key factor in improving our understanding of the impact of sedentary behavior(and patterns of sedentary time accumulation) on health is the use of objective measurement tools that collect date and time-stamped activity information. One such tool is the activP AL monitor. This thigh-worn device uses accelerometer-derived information about thigh position to determine the start and end of each period spent sitting/lying, standing, and stepping, as well as stepping speed, step counts, and postural transitions. The activP AL is increasingly being used within field-based research for its ability to measure sitting/lying via posture. We summarise key issues to consider when using the activP AL in physical activity and sedentary behavior field-based research with adult populations. It is intended that the findings and discussion points be informative for researchers who are currently using activP AL monitors or are intending to use them. Pre-data collection decisions, monitor preparation and distribution, data collection considerations, and manual and automated data processing possibilities are presented using examples from current literature and experiences from 2 research groups from the UK and Australia.
基金Supported by the National Natural Science Foundation of China (50736002,50806005,51006106)the Program for Changjiang Scholars and Innovative Research Team in University (IRT0952)
文摘Identifying the flow patterns is vital for understanding the complicated physical mechanisms in multiphase flows.For this purpose,electrical capacitance tomography(ECT) technique is considered as a promising visualization method for the flow pattern identification,in which image reconstruction algorithms play an important role.In this paper,a generalized dynamic reconstruction model,which integrates ECT measurement information and physical evolution information of the objects of interest,was presented.A generalized objective functional that simultaneously considers the spatial constraints,temporal constraints and dynamic evolution information of the objects of interest was proposed.Numerical simulations and experiments were implemented to evaluate the feasibility and efficiency of the proposed algorithm.For the cases considered in this paper,the proposed algorithm can well reconstruct the flow patterns,and the quality of the reconstructed images is improved,which indicates that the proposed algorithm is competent to reconstruct the flow patterns in the visualization of multiphase flows.
基金ACKNOWLEDGEMENT This work was partially supported by the National Natural Science Foundation of China under Grants No. 61202179, No. 61173089 SRF for ROCS, SEM and the Fundamental Research Funds for the Central Universities.
文摘In Web 2.0 era,the content on a web page is increasingly generated by end users,rather than limited number of administrators.Hence,large number of User Generated Content(UGC) has driven the explosion of content in the web.Thanks to UGC,the pattern of web usage has evolved from download dominated way to a hybrid one with both information download and upload.Large number of UGC has unveiled great capacity of information that is unavailable for researchers before,such as individual preferences,social connections,and etc.In this paper,we propose a novel model which studies the UGC in micro-blogging web sites,the largest and fastest information diffusion media online,and evaluate the social influence for an arbitrary individual.Experimental results show that our model outperforms state-of-the-art techniques in social influence evaluation in both the running time and accuracy.
基金supported by the National Science Foundation of China (grant Nos. 41271024, 41444430204, and J1210065)the Fundamental Research Funds for the Central Universities (Nos. lzujbky-2016-266 and lzujbky2016-270)
文摘Glacier length is a key morphological element that has many glaciological applications; however, it is often difficult to determine, especially for glaciers that cover larger spatial areas or those that exhibit frequent temporal change. In this paper, we describe a new Arc GIS-based method that can derive glacier flow lines for determining glacier length based on digital elevation model and glacier outlines. This method involves(1) extraction of the highest and lowest points on a glacier,(2) calculation of 10-m contour lines on the glacier from 10 m to 100 m height, and(3) connection of the midpoints of each contour line with the highest and the lowest points in order to create a flow line, which is subsequently smoothed. In order to assess the reliability of this method, we tested the algorithm's results against flow lines calculated using field measurements, analysing data from the Chinese Glacier Inventory, and manual interpretation. These data showed that the new automated method is effective in deriving glacier flow lines when contour lines are relatively large; in particular, when they are between 70 m and 100 m. Nonetheless, a key limitation of the algorithm is the requirement to automatically delete repeated and closed curves in the pre-treatment processes. In addition to calculating glacier flow lines for derivation of glacier length, this method also can be used to effectively determine glacier terminus change.
文摘Karl Marx (1973) scientifically predicted the appearance of some extraordinary tendencies of social development in the second half of the 20th century was given a common name of post-industrial or informational society and interpreted as post-bourgeois, post-capitalist, post-business society, and late capitalism. Autonomist Marxism and Perm philosophy school had separately come to a conclusion that all the phenomena noticed by the post-industrial theory could be adequately explained if we consider the historically new form of material labour appearing now. Marx (1973), who predicted this new form, named it automated, scientific, or universal labour. With the appearance of the universal labour, the wealth of the society depends on the universal human powers that help to involve the extensive powers of nature into the production process. Universal labour can not be averaged or measured by the labour time as the abstract labour; it implies high complexity and creativity. Involving increasingly powerful forces of nature and human society, it appears to be the labour of another essence and by its essence, it does not create value.
文摘In this study, we analyzed the swing motions of more experienced practitioner and new practitioner of iaido players by using tri-axial acceleration sensor and gyro sensor. Iaido is a modern Japanese martial art/sport. In this way, the acceleration and gyro sensor measurement enabled detailed motion information at the installation points to be displayed in a short time, thus making it possible to easily extract the objective problems. Although it was not possible to confirm by the acceleration and angular velocity measurements the detailed motion of the entire body as obtained in the 2D motion analysis with a high-speed camera, it was confirmed that the acceleration and gyro sensor is an evaluation means that can be installed easily and can provide the exercise information in a short time as an objective index.
文摘The heat parameters, the thermoanemometric flow-meter (TAF) errors and the experimental characteristics have been defined. The results of experiments were conducted with the help of physically-informational models allowing to realize all major thermal methods and their inherent informative options. The metrological evaluation was made and the sensitivity to the consumption of gas and liquid have been defined, their static and dynamic errors, followed by the comparison of costs according to these criteria. The developed method provides accurate measurement of volumetric flow of motor fuel 1.0-1.5% at heater temperature measurement accuracy of 1%.
基金Supported by the National Natural Science Foundation of China ( No. 60736043, 60672088) and the National Basic Research Program of China (No. 2009CB32005).
文摘Side information (SI) is one of the key issues in distributed video coding (DVC) and affects the compression performance of DVC largely. This paper proposes an SI refinement algorithm, in which the Wyner-Ziv (WZ) frame is split into two parts based on checkerboard pattern, and the two parts are encoded independently but decoded sequentially. In the decoding process, the part 1 is first decoded with the initial SI and partially decoded part (PDP) 1 is used to improve the motion vectors (MVs) and SI of both parts. At the next stage, the part 2 is decoded with the improved SI and PDP 2 is used to further refine MVs of the part 2. Then, SI of both parts are further refined. Simulation results show that the proposed algorithm can improve the peak signal to noise ratio (PSNR) by up to 1.43 dB when compared with traditional DVC codec.
文摘This study presents the Shannon and Renyi information entropy for both position and momentum space and the Fisher information for the position-dependent mass Schr¨odinger equation with the Frost-Musulin potential. The analysis of the quantum mechanical probability has been obtained via the Fisher information. The variance information of this potential is equally computed. This controls both the chemical properties and physical properties of some of the molecular systems. We have observed the behaviour of the Shannon entropy. Renyi entropy, Fisher information and variance with the quantum number n respectively.
基金supported by the National Natural Science Foundation of China (Grant Nos. 61071025 and 61172047)the Important Program of Hunan Provincial Education Department (Grant No. 06A038)+1 种基金Department of Education of Hunan Province (Grant No. 06C080)Hunan Provincial Natural Science Foundation, China (Grant No. 07JJ3013)
文摘Recently, a genuine six-qubit entangled state Isix) has been proposed [Chen P X, et al. Phys Rev A, 2006, 74: 032324]. This state does not belong to the well-known three types of multipartite entangled states, i.e., Greenberger-Home-Zeilinger (GHZ) state, W state, and linear cluster state. This state has many potential applications in quantum information processing. We pro- pose a scheme for generating such a genuine six-qubit entangled state for trapped ions in thermal motion. The scheme is insen- sitive to both the initial motional state and heating.
基金supported by the National Fundamental Research Program of China(Grant No.2010CB923202)the Specialized ResearchFund for the Doctoral Program of Education Ministry of China(GrantNo.20090005120008)the National Natural Science Foundation ofChina(Grant Nos.61177085 and 61205117)
文摘We present an efficient two-step entanglement concentration protocol(ECP)for three-level atoms trapped in one-sided optical micro-cavities in an arbitrary three-particle less-entangled W state,using the coherent state input-output process in low-Q cavity quantum electrodynamics system.In each step of the new proposed protocol,one of the three remote users prepares the auxiliary coherent optical pulses to perform cavity input-output process and then utilizes the standard homodyne measurement to discriminate the final outgoing coherent states.When both of the two steps are successful,remote parties can deterministically concentrate the less-entangled W state atoms to a standard maximally entangled W state.Compared with previous ECPs for W state,this protocol has some advantages and can be widely used in current quantum repeater and some quantum information processing tasks.
基金supported by the National Natural Science Foundation of China (Grant Nos. 40931056, 40874089)the National Basic Research Program of China ("973" Project) (Grant Nos. 2008CB425704)
文摘The energy budget of the magnetosphere-ionosphere (MI) system during 1998-2008 was examined by using Akasofu's epsilon function. The results showed that 1) the yearly average rate of solar wind energy input into the MI system was 4.51 GGJ (GGJ=1018 J), while the yearly average total dissipation was 4.30 GGJ; 2) the energy partitioning in the ring current and polar region was 56%:44%; 3) the energy input and dissipation processes continuously proceeded both in storm-substorm events and less disturbed intervals, suggesting the significant contribution of slow but long-lasting energy process during the less disturbance periods to the total energy budget. In addition, we found in this study an interesting phenomenon "self-adjustment ability" of the MI system which behaves just like a water reservoir. During solar active years, the input energy is more than the dissipated energy, implying that a portion of the input energy is not immediately released, but is stored in the magnetosphere. On the other hand, during less active years, the dissipated energy is more than the input energy, implying that the previously stored energy makes up for the energy input shortage in this period.
基金supported by the National Key Basic Research Special Foundation of China (Grant Nos. 2006CB921706 and 2010CB923200)the National Natural Science Foundation of China (Grant Nos. 10574160 and10725420)
文摘The dynamic evolution of a multi-level atom in the three-dimensional photonic crystal under an applied magnetic field is investigated.By combining the Zeeman effect with the photonic band gap effect,the dynamic quantum superposition states and steady quantum coherent trapping states of the atom can be flexibly controlled.This paves the way for coherent manipulation of quantum states in the solid-state system,which has important applications in quantum information processing.
基金Supported by the National Natural Science Foundation of China under Grant No.11274054the Creative Project of Graduate in University of Suzhou Science and Technology in No.SKCX16-006the Innovation Project of Graduate Education of Jiangsu Province No.JGLX15-150
文摘We investigate the dynamics of the precision of the parameter estimation in many driven atoms, each of which interacts with a local structured bosonic reservoir respectively. The evolution of quantum states for single driven atom is described by the time local quantum master equation. The dynamics of the quantum Fisher information for many entangled atoms is obtained by means of the supreoperator mapping. The estimation limit is superior to the standard quantum limit during a characteristic interval. At a given time, the precision of parameter estimation can be improved to a maximal value if the number of entangled atoms is chosen to be an optimal value. The optimal number of entangled atoms is determined by the dynamical property. The decay of quantum Fisher information is accelerated with the increase of the number of entangled atoms.
基金Supported by the National Natural Science Foundation of China under Grant No.61505053the Natural Science Foundation of Hunan Province under Grant No.2015JJ3092+1 种基金the Research Foundation of Education Bureau of Hunan Province,China under Grant No.16B177the School Foundation from the Hunan University of Arts and Science under Grant No.14ZD01
文摘A non-Markovianity measure based on Brukner–Zeilinger invariant information to characterize nonMarkovian effect of open systems undergoing unital dynamical maps is proposed. The method takes advantage of non-increasing property of the Brukner–Zeilinger invariant information under completely positive and trace-preserving unital maps. The simplicity of computing the Brukner–Zeilinger invariant information is the advantage of the proposed measure because of mainly depending on the purity of quantum state. The measure effectively captures the characteristics of non-Markovianity of unital dynamical maps. As some concrete application, we consider two typical non-Markovian noise channels, i.e., the phase damping channel and the random unitary channel to show the sensitivity of the proposed measure. By investigation, we find that the conditions of detecting the non-Markovianity for the phase damping channel are consistent with the results of existing measures for non-Markovianity, i.e., information flow, divisibility and quantum mutual information. However, for the random unitary channel non-Markovian conditions are same to that of the information flow, but is different from that of the divisibility and quantum mutual information.
基金Supported by the National Natural Science Foundation of China under Grant No.11374096the Natural Science Foundation of Guangdong Province under Grant No.2015A030310354the Projection of Enhancing School with Innovation of Guangdong Ocean University under Grant Nos.GDOU2014050251 and GDOU2014050252
文摘We study the quantum Fisher information(QFI) dynamics of the phase parameter in the enlarged cavityreservoir systems at zero temperature under two situations of large N limit and non-Markovian environment,respectively.We find an important relation that the total quantities of QFI of the cavity and reservoir are equal to unit during the dynamical evolution.The lost QFI of the cavity transfers to its corresponding reservoir with the same quantities simultaneously.Moreover,we also find that the detuning parameter and non-Markovian effect are two significant factors to affect the preservation of QFI.
基金Funding support from NSERC of Canadaa research fellowship at Department of Physics and Astronomy,University of British Columbia are acknowledged
文摘A strong analog classical simulation of general quantum evolution is proposed, which serves as a novel scheme in quantum computation and simulation. The scheme employs the approach of geometric quantum mechanics and quantum informational technique of quantum tomography, which applies broadly to cases of mixed states, nonunitary evolution, and infinite dimensional systems. The simulation provides an intriguing classical picture to probe quantum phenomena, namely, a coherent quantum dynamics can be viewed as a globally constrained classical Hamiltonian dynamics of a collection of coupled particles or strings. Efficiency analysis reveals a fundamental difference between the locality in real space and locality in Hilbert space, the latter enables efficient strong analog classical simulations. Examples are also studied to highlight the differences and gaps among various simulation methods.