The processing of measuri ng data plays an important role in reverse engineering. Based on grey system the ory, we first propose some methods to the processing of measuring data in revers e engineering. The measured d...The processing of measuri ng data plays an important role in reverse engineering. Based on grey system the ory, we first propose some methods to the processing of measuring data in revers e engineering. The measured data usually have some abnormalities. When the abnor mal data are eliminated by filtering, blanks are created. The grey generation an d GM(1,1) are used to create new data for these blanks. For the uneven data sequ en ce created by measuring error, the mean generation is used to smooth it and then the stepwise and smooth generations are used to improve the data sequence.展开更多
CO2 removal from biogas by water washing system was investigated with various parameters, including liquid/ gas ratio, pressure, temperature, and CO2 content. The results indicate that CO2 removal ratio could reach 34...CO2 removal from biogas by water washing system was investigated with various parameters, including liquid/ gas ratio, pressure, temperature, and CO2 content. The results indicate that CO2 removal ratio could reach 34.6%- 94.2% as liquid/gas ratio increased from 0.14 to 0.50. Increasing pressure (from 0.8 to 1.2 MPa) could improve gas purification with a constant inflow rate of gas. Temperature played a key role in the process and lower temper- ature in absorption tower was beneficial for reducing CO2 content. CO2 removal ratio could reach 24.4%-83.2% when CO2 content in the simulated gas was 25%-45%. The lowest CO2 content after absorption was 2.6% at 1.2 MPa with 400 L·h-1 gas flow and 200 L·h-1 water flow, which meets the requirement of CO2 content in natural Ras for vehicle fuel.展开更多
Biometric techniques require critical operations of digital processing for identification of individuals. In this context, this paper aims to develop a system for automatic processing of fingerprint identification by ...Biometric techniques require critical operations of digital processing for identification of individuals. In this context, this paper aims to develop a system for automatic processing of fingerprint identification by their minutiae using Artificial Neural Networks (ANN), which reveals to be highly effective. The ANN method implemented is a based on Multi-Layer Perceptron (MLP) model, which utilizes the algorithm of retro-propagation of gradient during the learning process. In such a process, the mean square error generated represents the specific parameter for the identification phase by comparing a fingerprint taken from a crime scene with those of a reference database.展开更多
Influenced by detectors' material, manufacturing technology etc, every detector in infrared focal plane array (IRFPA) will output different voltages even if their input radiation flux is the same. And this is calle...Influenced by detectors' material, manufacturing technology etc, every detector in infrared focal plane array (IRFPA) will output different voltages even if their input radiation flux is the same. And this is called non-uniformity of IRFPA. At the same time, the high background temperature, low temperature difference between targets and background and the low responsivity of IRFPA result in low contrast of infrared images. So non-uniformity correction and image enhancement are important techniques for IRFPA imaging system. This paper proposes a new real-time infrared image processing system based on Field Programmable Gate Array(FPGA). The system implements non-uniformity correction, image enhancernent and video synthesization etc. By using parallel architecture and pipeline technique, the system processing speed is as high as 50Mx12bits per second. It is appropriate greatly to a large IRFPA and a high frame frequency IRFPA imaging system. The system is miniatured in one FPGA.展开更多
In this article, we introduce the system of high throughput screening (HTS). Its role in new drug study and current development is described. The relationship between research achievements of genome study and new type...In this article, we introduce the system of high throughput screening (HTS). Its role in new drug study and current development is described. The relationship between research achievements of genome study and new type screening model of new drugs is emphasized. The personal opinions of current problems about HTS study in China are raised.展开更多
A systems approach is used to describe the generation and variation of wastewater in an urban area. This is a multivariable system and its combined response at the outlet of this system, which is usually the entrance ...A systems approach is used to describe the generation and variation of wastewater in an urban area. This is a multivariable system and its combined response at the outlet of this system, which is usually the entrance ofa wastewater treatment plant, depends on a number of environmental (precipitation and temperature) as well as social (size of the urban area, population changes, water consumption per capita) variables. There is a large number of available models and tools for describing the urban water system, however, the interactions between the individual components are rarely considered within the same modelling framework. In this paper a parsimonious methodology is proposed in order to understand and estimate the wastewater generation and its characteristics in an urban area using any information provided by the available data. The model incorporates both the flows of stormwater discharge and wastewater production that arrive to the wastewater treatment plant. A state dependent variable is introduced to simulate the consumptive uses in the urban area. Data availability and system's complexity affect the ability to achieve enhanced model performance, however, in the presented case study, preliminary results from the application of the presented model in the Greater Athens Area illustrate the potential of the conceptual modelling approach.展开更多
To improve efficiency of search engines, the query result cache has drawn much attention re- cently. According to the query processing and user's query logs locality, a new hybrid result cache strategy which associat...To improve efficiency of search engines, the query result cache has drawn much attention re- cently. According to the query processing and user's query logs locality, a new hybrid result cache strategy which associates with caching heat and worth is proposed to compute cache score in accord- ance with cost-aware strategies. Exactly, query repeated distance and query length factor are utilized to improve the static result policy, and the dynamic policy is adjusted by the caching worth. The hy- brid result cache is implemented in term of the document content and document ids (docIds) se- quence. Based on a score format and the new hybrid structure, an initial algorithm and a new rou- ting algorithm are designed for result cache. Experiments' results show that the improved caching policies decrease the average response time effectively, and increase the system throughput signifi- cantly. By choosing comfortable combination of page cache and docIds cache, the new hybrid cac- hing strategy almost reduces more than 20% of the only cache and docId-only cache. average query time compared with the basic page-展开更多
Jute fibre properties,viz. linear density,mechanical properties,and fibre staple length were analyzed in this paper. Morphology,lignin content,and composition analysis for jute fibres were investigated in order to giv...Jute fibre properties,viz. linear density,mechanical properties,and fibre staple length were analyzed in this paper. Morphology,lignin content,and composition analysis for jute fibres were investigated in order to give further understanding of the fibre properties changing during the chemical treatment and yarn producing processes. The results show that jute properties are greatly changed during the processes of chemical treatment,breaking carding,and finisher carding,whereas slight changes can be found in the processes of drawing,roving,and spinning.展开更多
Dynamitron DC1500/25/04 type EBA (Electron beam accelerator), model JOB 188, was manufactured by IBA Industrial (Radiation Dynamics, Inc.) and installed at IPEN-CNEN/SP, in 1978. The technical specifications of th...Dynamitron DC1500/25/04 type EBA (Electron beam accelerator), model JOB 188, was manufactured by IBA Industrial (Radiation Dynamics, Inc.) and installed at IPEN-CNEN/SP, in 1978. The technical specifications of the EBA are: energy 0.5 to 1.5 MeV; beam current: 0.3 to 25.0 mA; beam scanning: 60 to 120 cm; beam width: 25.4 mm and frequency: 100 Hz. Nowadays, this accelerator has been used for innumerable applications, such as: For sterilization of medical, pharmaceutical and biological products, treatment of industrial and domestic effluents and sludge, preservation and disinfestations of foods and agricultural products. Other important application are lignocellulosic material irradiation as a pre-treatment to produce ethanol bio-fuel, decontamination of pesticide packing, solid residues remediation, organic compounds removal from wastewater, treatment of effluent from petroleum production units, crosslinking of foams, wires and electric cables. Electron accelerator JOB 188 is, also, very important composite and nanocomposite materials and carbon fibers irradiation, irradiated grafting ion-exchange membranes for fuel cells application, natural polymers and multilayer packages irradiation and biodegradable blends production. The energy of the electron beam is calculated as a function of the current in the accelerator high-voltage divisor, taking into account the thickness and density of the material to be irradiated. This energy is calculated considering the electron through the entire material and the distance from the titanium foil window, so that the absorbed doses at the points of entrance and exit are equivalent on the material. The dose is directly proportional to the beam current and the exposure time of the material under the electron beam and inversely proportional to the scan width. The aim of this paper is to analyze the power system parameters of the EBA Dynamitron DC 1500/25/04, such as, voltage and RMS (Root-mean-square) current in the oscillator system, high voltage generator and waveform. For this purpose software developed in the Radiation Technology Center at IPEN/CNEN-SP to simulate the energy efficiency of this industrial accelerator. Finally, it is also targeted to compare theoretical dosimetry using parameters of energy and beam current with data from the accelerator power system. This knowledge and technology will be very useful and essential for the control system upgrade of EBA, mainly Dynamitron DC 1500/25/04 taking into consideration that radiation processing technology for industrial and environmental applications has been developed and used worldwide.展开更多
This research serves the primary purpose to support the reform of administration budgets for Taiwan Residents universities to optimize their document processing system. The main research method applied is quantitative...This research serves the primary purpose to support the reform of administration budgets for Taiwan Residents universities to optimize their document processing system. The main research method applied is quantitative analysis to explore the relationships between document quantity and each administration spending. The research observes that Taiwan Residents universities in general rely more on electronic systems to manage documents. Therefore, as proven by correlation test and regression model, personnel spending and miscellaneous spending are the only two categories which can help predict document flows. However, only miscellaneous spending is positively related to document quantity, so this category should be allocated with more funding. Personnel spending, on the contrary, should be less. For the long-term budgeting strategy, Taiwan Residents universities should begin with discovering problems from the existing system, design an allocation plan, execute the plan, and finally evaluate the outcomes. This project is on the first to explore the new academic research field which relates to logistics, budgeting, and university administration.展开更多
We investigate the bipartite entanglement dynamics of the system composed by three qubits A,B,and C.There is no interaction between A and B,and that of C and B is Dzyaloshinskii-Moriya (DM) spin-orbit interaction.We f...We investigate the bipartite entanglement dynamics of the system composed by three qubits A,B,and C.There is no interaction between A and B,and that of C and B is Dzyaloshinskii-Moriya (DM) spin-orbit interaction.We find that the purity of qubits A and B and the initial state of the qubit C are the two effective parameters tocontrol the entanglement dynamics of the bipartite subsystems.This study sheds some lights on the control of quantumentanglement,which would be helpful for quantum information processing.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 investigate quantum state tomography(QST) for pure states and quantum process tomography(QPT) for unitary channels via adaptive measurements. For a quantum system with a d-dimensional Hilbert space, we first propos...We investigate quantum state tomography(QST) for pure states and quantum process tomography(QPT) for unitary channels via adaptive measurements. For a quantum system with a d-dimensional Hilbert space, we first propose an adaptive protocol where only 2d. 1 measurement outcomes are used to accomplish the QST for all pure states. This idea is then extended to study QPT for unitary channels, where an adaptive unitary process tomography(AUPT) protocol of d2+d.1measurement outcomes is constructed for any unitary channel. We experimentally implement the AUPT protocol in a 2-qubit nuclear magnetic resonance system. We examine the performance of the AUPT protocol when applied to Hadamard gate, T gate(/8 phase gate), and controlled-NOT gate,respectively, as these gates form the universal gate set for quantum information processing purpose. As a comparison, standard QPT is also implemented for each gate. Our experimental results show that the AUPT protocol that reconstructing unitary channels via adaptive measurements significantly reduce the number of experiments required by standard QPT without considerable loss of fidelity.展开更多
The study of open quantum systems is important for fundamental issues of quantum physics as well as for technological applications such as quantum information processing. The interaction of a quantum system with its e...The study of open quantum systems is important for fundamental issues of quantum physics as well as for technological applications such as quantum information processing. The interaction of a quantum system with its environment is usually detrimental for the quantum properties of the system and leads to decoherence. However,sometimes a quantum control can lead to a coherent partial exchange of information between the system and the dynamics of the open system might become non-Markovian. In this article, we study experimentally discrete nonMarkovian open quantum system dynamics. We implement a local control protocol using linear optics for controlling the information flow between the open system and the environment. We show how the transition from Markovian to non-Markovian dynamics can be controlled using only local operations for the open system.展开更多
We consider the quantum measurements on a finite quantum system in coherence-vector representation. In this representation, all the density operators of an N-level(N≥2) quantum system constitute a convex set M^(N)emb...We consider the quantum measurements on a finite quantum system in coherence-vector representation. In this representation, all the density operators of an N-level(N≥2) quantum system constitute a convex set M^(N)embedded in an(N^2- 1)-dimensional Euclidean space R^((N^2)-1), and we find that an orthogonal measurement is an(N- 1)-dimensional projector operator on R^((N^2)-1). The states unchanged by an orthogonal measurement form an(N- 1)-dimensional simplex, and in the case when N is prime or power of prime, the space of the density operator is a direct sum of(N + 1) such simplices. The mathematical description of quantum measurement is plain in this representation, and this may have further applications in quantum information processing.展开更多
文摘The processing of measuri ng data plays an important role in reverse engineering. Based on grey system the ory, we first propose some methods to the processing of measuring data in revers e engineering. The measured data usually have some abnormalities. When the abnor mal data are eliminated by filtering, blanks are created. The grey generation an d GM(1,1) are used to create new data for these blanks. For the uneven data sequ en ce created by measuring error, the mean generation is used to smooth it and then the stepwise and smooth generations are used to improve the data sequence.
基金Supported by the National Technology Research and Development Program of China(2008AA062402)the China-US International Cooperation Project(2011DFA90800)the Ministry of Science and Technology,China
文摘CO2 removal from biogas by water washing system was investigated with various parameters, including liquid/ gas ratio, pressure, temperature, and CO2 content. The results indicate that CO2 removal ratio could reach 34.6%- 94.2% as liquid/gas ratio increased from 0.14 to 0.50. Increasing pressure (from 0.8 to 1.2 MPa) could improve gas purification with a constant inflow rate of gas. Temperature played a key role in the process and lower temper- ature in absorption tower was beneficial for reducing CO2 content. CO2 removal ratio could reach 24.4%-83.2% when CO2 content in the simulated gas was 25%-45%. The lowest CO2 content after absorption was 2.6% at 1.2 MPa with 400 L·h-1 gas flow and 200 L·h-1 water flow, which meets the requirement of CO2 content in natural Ras for vehicle fuel.
文摘Biometric techniques require critical operations of digital processing for identification of individuals. In this context, this paper aims to develop a system for automatic processing of fingerprint identification by their minutiae using Artificial Neural Networks (ANN), which reveals to be highly effective. The ANN method implemented is a based on Multi-Layer Perceptron (MLP) model, which utilizes the algorithm of retro-propagation of gradient during the learning process. In such a process, the mean square error generated represents the specific parameter for the identification phase by comparing a fingerprint taken from a crime scene with those of a reference database.
文摘Influenced by detectors' material, manufacturing technology etc, every detector in infrared focal plane array (IRFPA) will output different voltages even if their input radiation flux is the same. And this is called non-uniformity of IRFPA. At the same time, the high background temperature, low temperature difference between targets and background and the low responsivity of IRFPA result in low contrast of infrared images. So non-uniformity correction and image enhancement are important techniques for IRFPA imaging system. This paper proposes a new real-time infrared image processing system based on Field Programmable Gate Array(FPGA). The system implements non-uniformity correction, image enhancernent and video synthesization etc. By using parallel architecture and pipeline technique, the system processing speed is as high as 50Mx12bits per second. It is appropriate greatly to a large IRFPA and a high frame frequency IRFPA imaging system. The system is miniatured in one FPGA.
文摘In this article, we introduce the system of high throughput screening (HTS). Its role in new drug study and current development is described. The relationship between research achievements of genome study and new type screening model of new drugs is emphasized. The personal opinions of current problems about HTS study in China are raised.
文摘A systems approach is used to describe the generation and variation of wastewater in an urban area. This is a multivariable system and its combined response at the outlet of this system, which is usually the entrance ofa wastewater treatment plant, depends on a number of environmental (precipitation and temperature) as well as social (size of the urban area, population changes, water consumption per capita) variables. There is a large number of available models and tools for describing the urban water system, however, the interactions between the individual components are rarely considered within the same modelling framework. In this paper a parsimonious methodology is proposed in order to understand and estimate the wastewater generation and its characteristics in an urban area using any information provided by the available data. The model incorporates both the flows of stormwater discharge and wastewater production that arrive to the wastewater treatment plant. A state dependent variable is introduced to simulate the consumptive uses in the urban area. Data availability and system's complexity affect the ability to achieve enhanced model performance, however, in the presented case study, preliminary results from the application of the presented model in the Greater Athens Area illustrate the potential of the conceptual modelling approach.
基金Supported by the National Natural Science Foundation of China(No.61173024)
文摘To improve efficiency of search engines, the query result cache has drawn much attention re- cently. According to the query processing and user's query logs locality, a new hybrid result cache strategy which associates with caching heat and worth is proposed to compute cache score in accord- ance with cost-aware strategies. Exactly, query repeated distance and query length factor are utilized to improve the static result policy, and the dynamic policy is adjusted by the caching worth. The hy- brid result cache is implemented in term of the document content and document ids (docIds) se- quence. Based on a score format and the new hybrid structure, an initial algorithm and a new rou- ting algorithm are designed for result cache. Experiments' results show that the improved caching policies decrease the average response time effectively, and increase the system throughput signifi- cantly. By choosing comfortable combination of page cache and docIds cache, the new hybrid cac- hing strategy almost reduces more than 20% of the only cache and docId-only cache. average query time compared with the basic page-
基金National Key Technologies R&D Program of China (No.2007BAE41B01)
文摘Jute fibre properties,viz. linear density,mechanical properties,and fibre staple length were analyzed in this paper. Morphology,lignin content,and composition analysis for jute fibres were investigated in order to give further understanding of the fibre properties changing during the chemical treatment and yarn producing processes. The results show that jute properties are greatly changed during the processes of chemical treatment,breaking carding,and finisher carding,whereas slight changes can be found in the processes of drawing,roving,and spinning.
文摘Dynamitron DC1500/25/04 type EBA (Electron beam accelerator), model JOB 188, was manufactured by IBA Industrial (Radiation Dynamics, Inc.) and installed at IPEN-CNEN/SP, in 1978. The technical specifications of the EBA are: energy 0.5 to 1.5 MeV; beam current: 0.3 to 25.0 mA; beam scanning: 60 to 120 cm; beam width: 25.4 mm and frequency: 100 Hz. Nowadays, this accelerator has been used for innumerable applications, such as: For sterilization of medical, pharmaceutical and biological products, treatment of industrial and domestic effluents and sludge, preservation and disinfestations of foods and agricultural products. Other important application are lignocellulosic material irradiation as a pre-treatment to produce ethanol bio-fuel, decontamination of pesticide packing, solid residues remediation, organic compounds removal from wastewater, treatment of effluent from petroleum production units, crosslinking of foams, wires and electric cables. Electron accelerator JOB 188 is, also, very important composite and nanocomposite materials and carbon fibers irradiation, irradiated grafting ion-exchange membranes for fuel cells application, natural polymers and multilayer packages irradiation and biodegradable blends production. The energy of the electron beam is calculated as a function of the current in the accelerator high-voltage divisor, taking into account the thickness and density of the material to be irradiated. This energy is calculated considering the electron through the entire material and the distance from the titanium foil window, so that the absorbed doses at the points of entrance and exit are equivalent on the material. The dose is directly proportional to the beam current and the exposure time of the material under the electron beam and inversely proportional to the scan width. The aim of this paper is to analyze the power system parameters of the EBA Dynamitron DC 1500/25/04, such as, voltage and RMS (Root-mean-square) current in the oscillator system, high voltage generator and waveform. For this purpose software developed in the Radiation Technology Center at IPEN/CNEN-SP to simulate the energy efficiency of this industrial accelerator. Finally, it is also targeted to compare theoretical dosimetry using parameters of energy and beam current with data from the accelerator power system. This knowledge and technology will be very useful and essential for the control system upgrade of EBA, mainly Dynamitron DC 1500/25/04 taking into consideration that radiation processing technology for industrial and environmental applications has been developed and used worldwide.
文摘This research serves the primary purpose to support the reform of administration budgets for Taiwan Residents universities to optimize their document processing system. The main research method applied is quantitative analysis to explore the relationships between document quantity and each administration spending. The research observes that Taiwan Residents universities in general rely more on electronic systems to manage documents. Therefore, as proven by correlation test and regression model, personnel spending and miscellaneous spending are the only two categories which can help predict document flows. However, only miscellaneous spending is positively related to document quantity, so this category should be allocated with more funding. Personnel spending, on the contrary, should be less. For the long-term budgeting strategy, Taiwan Residents universities should begin with discovering problems from the existing system, design an allocation plan, execute the plan, and finally evaluate the outcomes. This project is on the first to explore the new academic research field which relates to logistics, budgeting, and university administration.
基金Supported by the National Natural Science Foundation of China under Grant Nos.10535010 and 10775123Research Fund of Education Ministry under Grant No.20070284016+1 种基金the Natural Science and Technology Foundation of Guizhou Province under Grant Nos.[2009]2267the Doctor funding of Guizhou Normal University
文摘We investigate the bipartite entanglement dynamics of the system composed by three qubits A,B,and C.There is no interaction between A and B,and that of C and B is Dzyaloshinskii-Moriya (DM) spin-orbit interaction.We find that the purity of qubits A and B and the initial state of the qubit C are the two effective parameters tocontrol the entanglement dynamics of the bipartite subsystems.This study sheds some lights on the control of quantumentanglement,which would be helpful for quantum information processing.
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 Natural Sciences and Engineering Research Council of Canada(NSERC)the Canadian Institute for Advanced Research(CIFAR)+3 种基金the National Natural Science Foundation of China(Grant Nos11175094,91221205,11375167,11227901 and 91021005)the National Basic Research Program of China(Grant No.2015CB921002)the National Key Basic Research Program(NKBRP)(Grant Nos.2013CB921800and 2014CB848700)the National Science Fund for Distinguished Young Scholars(Grant No.11425523)
文摘We investigate quantum state tomography(QST) for pure states and quantum process tomography(QPT) for unitary channels via adaptive measurements. For a quantum system with a d-dimensional Hilbert space, we first propose an adaptive protocol where only 2d. 1 measurement outcomes are used to accomplish the QST for all pure states. This idea is then extended to study QPT for unitary channels, where an adaptive unitary process tomography(AUPT) protocol of d2+d.1measurement outcomes is constructed for any unitary channel. We experimentally implement the AUPT protocol in a 2-qubit nuclear magnetic resonance system. We examine the performance of the AUPT protocol when applied to Hadamard gate, T gate(/8 phase gate), and controlled-NOT gate,respectively, as these gates form the universal gate set for quantum information processing purpose. As a comparison, standard QPT is also implemented for each gate. Our experimental results show that the AUPT protocol that reconstructing unitary channels via adaptive measurements significantly reduce the number of experiments required by standard QPT without considerable loss of fidelity.
基金supported by the Magnus Ehrnrooth Foundation and Academy of Finland (287750)National Natural Science Foundation of China (61327901, 11274289 and 11325419)+1 种基金the Strategic Priority Research Program (B) of the Chinese Academy of Sciences (XDB01030300)C.F.L. and J.P. acknowledge financial support from the EU Collaborative project Qu Pro CS (Grant Agreement 641277)
文摘The study of open quantum systems is important for fundamental issues of quantum physics as well as for technological applications such as quantum information processing. The interaction of a quantum system with its environment is usually detrimental for the quantum properties of the system and leads to decoherence. However,sometimes a quantum control can lead to a coherent partial exchange of information between the system and the dynamics of the open system might become non-Markovian. In this article, we study experimentally discrete nonMarkovian open quantum system dynamics. We implement a local control protocol using linear optics for controlling the information flow between the open system and the environment. We show how the transition from Markovian to non-Markovian dynamics can be controlled using only local operations for the open system.
基金supported by the National Natural Science Foundation of China(Grant Nos.11405136 and 11547311)the Fundamental Research Funds for the Central Universities of China(Grant No.2682014BR056)
文摘We consider the quantum measurements on a finite quantum system in coherence-vector representation. In this representation, all the density operators of an N-level(N≥2) quantum system constitute a convex set M^(N)embedded in an(N^2- 1)-dimensional Euclidean space R^((N^2)-1), and we find that an orthogonal measurement is an(N- 1)-dimensional projector operator on R^((N^2)-1). The states unchanged by an orthogonal measurement form an(N- 1)-dimensional simplex, and in the case when N is prime or power of prime, the space of the density operator is a direct sum of(N + 1) such simplices. The mathematical description of quantum measurement is plain in this representation, and this may have further applications in quantum information processing.