WorldWideScience

Sample records for spinning reserve requirements

  1. Calculation program development for spinning reserve

    International Nuclear Information System (INIS)

    1979-01-01

    This study is about optimal holding of spinning reserve and optimal operation for it. It deals with the purpose and contents of the study, introduction of the spinning reserve electricity, speciality of the spinning reserve power, the result of calculation, analysis for limited method of optimum load, calculation of requirement for spinning reserve, analysis on measurement of system stability with summary, purpose of the analysis, cause of impact of the accident, basics on measurement of spinning reserve and conclusion. It has the reference on explanation for design of spinning reserve power program and using and trend about spinning reserve power in Korea.

  2. A new spinning reserve requirement forecast method for deregulated electricity markets

    International Nuclear Information System (INIS)

    Amjady, Nima; Keynia, Farshid

    2010-01-01

    Ancillary services are necessary for maintaining the security and reliability of power systems and constitute an important part of trade in competitive electricity markets. Spinning Reserve (SR) is one of the most important ancillary services for saving power system stability and integrity in response to contingencies and disturbances that continuously occur in the power systems. Hence, an accurate day-ahead forecast of SR requirement helps the Independent System Operator (ISO) to conduct a reliable and economic operation of the power system. However, SR signal has complex, non-stationary and volatile behavior along the time domain and depends greatly on system load. In this paper, a new hybrid forecast engine is proposed for SR requirement prediction. The proposed forecast engine has an iterative training mechanism composed of Levenberg-Marquadt (LM) learning algorithm and Real Coded Genetic Algorithm (RCGA), implemented on the Multi-Layer Perceptron (MLP) neural network. The proposed forecast methodology is examined by means of real data of Pennsylvania-New Jersey-Maryland (PJM) electricity market and the California ISO (CAISO) controlled grid. The obtained forecast results are presented and compared with those of the other SR forecast methods. (author)

  3. A new spinning reserve requirement forecast method for deregulated electricity markets

    Energy Technology Data Exchange (ETDEWEB)

    Amjady, Nima; Keynia, Farshid [Department of Electrical Engineering, Semnan University, Semnan (Iran)

    2010-06-15

    Ancillary services are necessary for maintaining the security and reliability of power systems and constitute an important part of trade in competitive electricity markets. Spinning Reserve (SR) is one of the most important ancillary services for saving power system stability and integrity in response to contingencies and disturbances that continuously occur in the power systems. Hence, an accurate day-ahead forecast of SR requirement helps the Independent System Operator (ISO) to conduct a reliable and economic operation of the power system. However, SR signal has complex, non-stationary and volatile behavior along the time domain and depends greatly on system load. In this paper, a new hybrid forecast engine is proposed for SR requirement prediction. The proposed forecast engine has an iterative training mechanism composed of Levenberg-Marquadt (LM) learning algorithm and Real Coded Genetic Algorithm (RCGA), implemented on the Multi-Layer Perceptron (MLP) neural network. The proposed forecast methodology is examined by means of real data of Pennsylvania-New Jersey-Maryland (PJM) electricity market and the California ISO (CAISO) controlled grid. The obtained forecast results are presented and compared with those of the other SR forecast methods. (author)

  4. Replacing reserve requirements

    OpenAIRE

    Edward J. Stevens

    1993-01-01

    An examination of the fading significance of the Federal Reserve System's reserve requirements and the recent flowering of required clearing balances, a rapidly growing feature of Reserve Bank operations.

  5. Demand Response Spinning Reserve Demonstration

    Energy Technology Data Exchange (ETDEWEB)

    Eto, Joseph H.; Nelson-Hoffman, Janine; Torres, Carlos; Hirth,Scott; Yinger, Bob; Kueck, John; Kirby, Brendan; Bernier, Clark; Wright,Roger; Barat, A.; Watson, David S.

    2007-05-01

    The Demand Response Spinning Reserve project is a pioneeringdemonstration of how existing utility load-management assets can providean important electricity system reliability resource known as spinningreserve. Using aggregated demand-side resources to provide spinningreserve will give grid operators at the California Independent SystemOperator (CAISO) and Southern California Edison (SCE) a powerful, newtool to improve system reliability, prevent rolling blackouts, and lowersystem operating costs.

  6. Joint energy and spinning reserve dispatching and pricing

    International Nuclear Information System (INIS)

    Rashidinejad, M.; Song, Y.-H.; Javidi Dasht-Bayaz, M.H.

    2000-01-01

    Unpredictable load demand variations, and also sudden generation interruption, may cause imbalance in power systems. To prevent any blackout and to reduce such total power imbalance, spinning reserve can provide electric power system ability to respond. Adequate amount of spinning reserve should be based on economy and risk as an optimal decision making. This paper uses Quadratic Programming (QP) method to solve Joint Energy and Spinning Reserve Dispatch (JESRD) problem and derives the optimal price of spinning reserve. In JESRD, Unserved Energy Cost (UEC) is considered as an Opportunity Cost of Spinning Reserve (OCSR). To distribute the System Reserve Requirements (SRR) among generation units, two different models, Fixed Reserve Percentage (FRP) or fixed allocation model and Non-Fixed Reserve Percentage (NFRP) or flexible allocation model has been investigated. Numerical results on a 5-bus test system and the 30-bus IEEE standard system, considering FRP and NFRP models are included. (author)

  7. 77 FR 21846 - Reserve Requirements of Depository Institutions: Reserves Simplification

    Science.gov (United States)

    2012-04-12

    ... Requirements of Depository Institutions: Reserves Simplification AGENCY: Board of Governors of the Federal Reserve System. ACTION: Final rule. SUMMARY: The Board is amending Regulation D, Reserve Requirements of Depository Institutions, to simplify the administration of reserve requirements. The final rule creates a...

  8. 77 FR 66361 - Reserve Requirements of Depository Institutions: Reserves Simplification

    Science.gov (United States)

    2012-11-05

    ... Requirements of Depository Institutions: Reserves Simplification AGENCY: Board of Governors of the Federal... (Reserve Requirements of Depository Institutions) published in the Federal Register on April 12, 2012. The... simplifications related to the administration of reserve requirements: 1. Create a common two-week maintenance...

  9. Reserve Requirements and Monetary Management; An Introduction

    OpenAIRE

    International Monetary Fund

    1993-01-01

    Reserve requirements are widely used by central banks as a means to improve monetary control, an instrument for policy implementation, a source of revenue, and a safeguard of bank liquidity. The effectiveness of reserve requirements in fulfilling these functions is reviewed, and the detailed modalities of their use are examined. Reserve requirements in a sample of developing countries are described.

  10. 42 CFR 417.934 - Reserve requirement.

    Science.gov (United States)

    2010-10-01

    ... 42 Public Health 3 2010-10-01 2010-10-01 false Reserve requirement. 417.934 Section 417.934 Public... PLANS Administration of Outstanding Loans and Loan Guarantees § 417.934 Reserve requirement. (a) Timing... section 1305 of the PHS Act was required to establish a restricted reserve account on the earlier of the...

  11. Reserve requirement systems in OECD countries

    OpenAIRE

    Yueh-Yun C. O’Brien

    2007-01-01

    This paper compares the reserve requirements of OECD countries. Reserve requirements are the minimum percentages or amounts of liabilities that depository institutions are required to keep in cash or as deposits with their central banks. To facilitate monetary policy implementation, twenty-four of the thirty OECD countries impose reserve requirements to influence their banking systems’ demand for liquidity. These include twelve OECD countries that are also members of the European Economic and...

  12. 24 CFR 266.110 - Reserve requirements.

    Science.gov (United States)

    2010-04-01

    ... HOUSING FINANCE AGENCY RISK-SHARING PROGRAM FOR INSURED AFFORDABLE MULTIFAMILY PROJECT LOANS Housing Finance Agency Requirements § 266.110 Reserve requirements. (a) HFAs with top-tier designation or overall...

  13. Required reserves as a credit policy tool

    OpenAIRE

    Mimir, Yasin; Sunel, Enes; Taskin, Temel

    2012-01-01

    This paper conducts a quantitative investigation of the role of reserve requirements as a macroprudential policy tool. We build a monetary DSGE model with a banking sector in which (i) an agency problem between households and banks leads to endogenous capital constraints for banks in obtaining funds from households, (ii) banks are subject to time-varying reserve requirements that countercyclically respond to expected credit growth, (iii) households face cash-in-advance constraints, requiring ...

  14. A stochastic security approach to energy and spinning reserve scheduling considering demand response program

    International Nuclear Information System (INIS)

    Partovi, Farzad; Nikzad, Mehdi; Mozafari, Babak; Ranjbar, Ali Mohamad

    2011-01-01

    In this paper a new algorithm for allocating energy and determining the optimum amount of network active power reserve capacity and the share of generating units and demand side contribution in providing reserve capacity requirements for day-ahead market is presented. In the proposed method, the optimum amount of reserve requirement is determined based on network security set by operator. In this regard, Expected Load Not Supplied (ELNS) is used to evaluate system security in each hour. The proposed method has been implemented over the IEEE 24-bus test system and the results are compared with a deterministic security approach, which considers certain and fixed amount of reserve capacity in each hour. This comparison is done from economic and technical points of view. The promising results show the effectiveness of the proposed model which is formulated as mixed integer linear programming (MILP) and solved by GAMS software. -- Highlights: → Determination of optimal spinning reserve capacity requirement in order to satisfy desired security level set by system operator based on stochastic approach. → Scheduling energy and spinning reserve markets simultaneously. → Comparing the stochastic approach with deterministic approach to determine the advantages and disadvantages of each. → Examine the effect of demand response participation in reserve market to provide spinning reserve.

  15. Spinning reserve quantification by a stochastic–probabilistic scheme for smart power systems with high wind penetration

    International Nuclear Information System (INIS)

    Khazali, Amirhossein; Kalantar, Mohsen

    2015-01-01

    Highlights: • A stochastic–probabilistic approach is proposed for spinning reserve quantification. • A new linearized formulation integrating reliability metrics is presented. • The framework manages the reserve provided by responsive loads and storage systems. • The proposed method is capable of detaching the spinning reserve for different uses. - Abstract: This paper introduces a novel spinning reserve quantification scheme based on a hybrid stochastic–probabilistic approach for smart power systems including high penetration of wind generation. In this research the required spinning reserve is detached into two main parts. The first part of the reserve is procured to overcome imbalances between load and generation in the system. The second part of the required spinning reserve is scheduled according to the probability of unit outages. In order to overcome uncertainties caused by wind generation and load forecasting errors different scenarios of wind generation and load uncertainties are generated. For each scenario the reserve deployed by different components are taken account as the first part of the required reserve which is used to overcome imbalances. The second part of the required reserve is based on reliability constraints. The total expected energy not supplied (TEENS) is the reliability criterion which determines the second part of the required spinning reserve to overcome unit outage possibilities. This formulation permits the independent system operator to purchase the two different types of reserve with different prices. The introduced formulation for reserve quantification is also capable of managing and detaching the reserve provided by responsive loads and energy storage devices. The problem is formulated as a mixed integer linear programming (MILP) problem including linearized formulations for reliability metrics. Obtained results show the efficiency of the proposed approach compared with the conventional stochastic and deterministic

  16. 12 CFR 204.4 - Computation of required reserves.

    Science.gov (United States)

    2010-01-01

    ... RESERVE REQUIREMENTS OF DEPOSITORY INSTITUTIONS (REGULATION D) § 204.4 Computation of required reserves. (a) In determining the reserve requirement under this part, the amount of cash items in process of... reserves are computed by applying the reserve requirement ratios below to net transaction accounts...

  17. 76 FR 68064 - Reserve Requirements of Depository Institutions

    Science.gov (United States)

    2011-11-03

    ... Reserve Requirements of Depository Institutions AGENCY: Board of Governors of the Federal Reserve System. ACTION: Final rule. SUMMARY: The Board is amending Regulation D, Reserve Requirements of Depository Institutions, to reflect the annual indexing of the reserve requirement exemption amount and the low reserve...

  18. 12 CFR 204.7 - Supplemental reserve requirement.

    Science.gov (United States)

    2010-01-01

    ... 12 Banks and Banking 2 2010-01-01 2010-01-01 false Supplemental reserve requirement. 204.7 Section... RESERVE REQUIREMENTS OF DEPOSITORY INSTITUTIONS (REGULATION D) § 204.7 Supplemental reserve requirement... reserve requirement on every depository institution of not more than 4 percent of its total transaction...

  19. 12 CFR 204.9 - Emergency reserve requirement.

    Science.gov (United States)

    2010-01-01

    ... 12 Banks and Banking 2 2010-01-01 2010-01-01 false Emergency reserve requirement. 204.9 Section... RESERVE REQUIREMENTS OF DEPOSITORY INSTITUTIONS (REGULATION D) § 204.9 Emergency reserve requirement. (a..., additional reserve requirements on depository institutions at any ratio on any liability upon a finding by at...

  20. 47 CFR 10.540 - Attestation requirement. [Reserved

    Science.gov (United States)

    2010-10-01

    ... 47 Telecommunication 1 2010-10-01 2010-10-01 false Attestation requirement. [Reserved] 10.540 Section 10.540 Telecommunication FEDERAL COMMUNICATIONS COMMISSION GENERAL COMMERCIAL MOBILE ALERT SYSTEM Equipment Requirements § 10.540 Attestation requirement. [Reserved] ...

  1. 75 FR 65563 - Reserve Requirements of Depository Institutions

    Science.gov (United States)

    2010-10-26

    ... Requirements of Depository Institutions AGENCY: Board of Governors of the Federal Reserve System. ACTION: Final rule. SUMMARY: The Board is amending Regulation D, Reserve Requirements of Depository Institutions, to reflect the annual indexing of the reserve requirement exemption amount and the low reserve tranche for...

  2. 78 FR 66249 - Reserve Requirements of Depository Institutions

    Science.gov (United States)

    2013-11-05

    ... Requirements of Depository Institutions AGENCY: Board of Governors of the Federal Reserve System. ACTION: Final rule. SUMMARY: The Board is amending Regulation D, Reserve Requirements of Depository Institutions, to reflect the annual indexing of the reserve requirement exemption amount and the low reserve tranche for...

  3. 77 FR 65773 - Reserve Requirements of Depository Institutions

    Science.gov (United States)

    2012-10-31

    ... Requirements of Depository Institutions AGENCY: Board of Governors of the Federal Reserve System. ACTION: Final rule. SUMMARY: The Board is amending Regulation D, Reserve Requirements of Depository Institutions, to reflect the annual indexing of the reserve requirement exemption amount and the low reserve tranche for...

  4. 7 CFR 981.51 - Requirements for reserve.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 8 2010-01-01 2010-01-01 false Requirements for reserve. 981.51 Section 981.51... Regulating Handling Volume Regulation § 981.51 Requirements for reserve. Each handler may satisfy his reserve... include grade requirements for reserve almonds delivered to human consumption outlets. [41 FR 26853, June...

  5. A public finance analysis of multiple reserve requirements

    OpenAIRE

    Espinosa-Vega, Marco; Russell, Steven

    1998-01-01

    This paper analyzes multiple reserve requirements of the type that have been imposed by a number of developing countries. We show that previous theoretical work on this topic has not succeeded in providing a social welfare rationale for the existence of multiple reserve requirements: in the basic reserve requirements model, any allocation that can be supported by a multiple-reserves regime can also be supported by a single-bond reserve requirement. We go on to present extended versions of the...

  6. 20 CFR 617.60 - Administration requirements. [Reserved

    Science.gov (United States)

    2010-04-01

    ... 20 Employees' Benefits 3 2010-04-01 2010-04-01 false Administration requirements. [Reserved] 617.60 Section 617.60 Employees' Benefits EMPLOYMENT AND TRAINING ADMINISTRATION, DEPARTMENT OF LABOR... Agencies § 617.60 Administration requirements. [Reserved] ...

  7. 40 CFR 429.12 - Monitoring requirements. [Reserved

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 29 2010-07-01 2010-07-01 false Monitoring requirements. [Reserved] 429.12 Section 429.12 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT... Monitoring requirements. [Reserved] ...

  8. 24 CFR 884.225 - PHA reporting requirements. [Reserved

    Science.gov (United States)

    2010-04-01

    ... reporting requirements. [Reserved] ... 24 Housing and Urban Development 4 2010-04-01 2010-04-01 false PHA reporting requirements. [Reserved] 884.225 Section 884.225 Housing and Urban Development Regulations Relating to Housing and Urban...

  9. 40 CFR 410.02 - Monitoring requirements. [Reserved

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 28 2010-07-01 2010-07-01 true Monitoring requirements. [Reserved] 410.02 Section 410.02 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT... requirements. [Reserved] ...

  10. Coordination of bidding strategies in day-ahead energy and spinning reserve markets

    International Nuclear Information System (INIS)

    Fushuan Wen; David, A.K.

    2002-01-01

    In this paper, the problem of building optimally coordinated bidding strategies for competitive suppliers in day-ahead energy and spinning reserve markets is addressed. It is assumed that each supplier bids 24 linear energy supply functions and 24 linear spinning reserve supply functions, one for each hour, into the energy and spinning reserve markets, respectively, and each market is cleared separately and simultaneously for all the 24 delivery hours. Each supplier makes decisions on unit commitment and chooses the coefficients in the linear energy and spinning reserve supply functions to maximise total benefits, subject to expectations about how rival suppliers will bid in both markets. Two different bidding schemes have been suggested for each hour, and based on them an overall coordinated bidding strategy in the day-ahead energy and spinning reserve market is then developed. Stochastic optimisation models are first developed to describe these two different bidding schemes and a genetic algorithm (GA) is then used to build the optimally coordinated bidding strategies for each scheme and to develop an overall bidding strategy for the day-ahead energy and spinning reserve markets. A numerical example is utilised to illustrate the essential features of the method. (Author)

  11. 12 CFR 652.20 - Liquidity reserve management and requirements.

    Science.gov (United States)

    2010-01-01

    ... 12 Banks and Banking 6 2010-01-01 2010-01-01 false Liquidity reserve management and requirements... AGRICULTURAL MORTGAGE CORPORATION FUNDING AND FISCAL AFFAIRS Investment Management § 652.20 Liquidity reserve management and requirements. (a) Minimum liquidity reserve requirement. Within 24 months of this rule...

  12. 12 CFR 615.5134 - Liquidity reserve requirement.

    Science.gov (United States)

    2010-01-01

    ... 12 Banks and Banking 6 2010-01-01 2010-01-01 false Liquidity reserve requirement. 615.5134 Section..., LOAN POLICIES AND OPERATIONS, AND FUNDING OPERATIONS Investment Management § 615.5134 Liquidity reserve requirement. (a) Each Farm Credit bank must maintain a liquidity reserve, discounted in accordance with...

  13. Reserve requirements and the bank lending channel in China

    OpenAIRE

    Fungácová , Zuzana; Nuutilainen , Riikka; Weill , Laurent

    2015-01-01

    This paper examines how reserve requirements influence the transmission of monetary policy through the bank lending channel in China while also taking into account the role of bank ownership. The implementation of Chinese monetary policy is characterized by the reliance on the reserve requirements as a regular policy tool with frequent adjustments. Using a large dataset of 170 Chinese banks for the period 2004–2013, we analyze the reaction of loan supply to changes in reserve requirements. We...

  14. How required reserve ratio affects distribution and velocity of money

    Science.gov (United States)

    Xi, Ning; Ding, Ning; Wang, Yougui

    2005-11-01

    In this paper the dependence of wealth distribution and the velocity of money on the required reserve ratio is examined based on a random transfer model of money and computer simulations. A fractional reserve banking system is introduced to the model where money creation can be achieved by bank loans and the monetary aggregate is determined by the monetary base and the required reserve ratio. It is shown that monetary wealth follows asymmetric Laplace distribution and latency time of money follows exponential distribution. The expression of monetary wealth distribution and that of the velocity of money in terms of the required reserve ratio are presented in a good agreement with simulation results.

  15. How Required Reserve Ratio Affects Distribution and Velocity of Money

    OpenAIRE

    Xi, Ning; Ding, Ning; Wang, Yougui

    2005-01-01

    In this paper the dependence of wealth distribution and the velocity of money on the required reserve ratio is examined based on a random transfer model of money and computer simulations. A fractional reserve banking system is introduced to the model where money creation can be achieved by bank loans and the monetary aggregate is determined by the monetary base and the required reserve ratio. It is shown that monetary wealth follows asymmetric Laplace distribution and latency time of money fo...

  16. Computational quantum chemistry for single Heisenberg spin couplings made simple: Just one spin flip required

    International Nuclear Information System (INIS)

    Mayhall, Nicholas J.; Head-Gordon, Martin

    2014-01-01

    We highlight a simple strategy for computing the magnetic coupling constants, J, for a complex containing two multiradical centers. On the assumption that the system follows Heisenberg Hamiltonian physics, J is obtained from a spin-flip electronic structure calculation where only a single electron is excited (and spin-flipped), from the single reference with maximum S ^ z , M, to the M − 1 manifold, regardless of the number of unpaired electrons, 2M, on the radical centers. In an active space picture involving 2M orbitals, only one β electron is required, together with only one α hole. While this observation is extremely simple, the reduction in the number of essential configurations from exponential in M to only linear provides dramatic computational benefits. This (M, M − 1) strategy for evaluating J is an unambiguous, spin-pure, wave function theory counterpart of the various projected broken symmetry density functional theory schemes, and likewise gives explicit energies for each possible spin-state that enable evaluation of properties. The approach is illustrated on five complexes with varying numbers of unpaired electrons, for which one spin-flip calculations are used to compute J. Some implications for further development of spin-flip methods are discussed

  17. Use and Limitations of the Reserve Requirement Policy in Montenegro

    Directory of Open Access Journals (Sweden)

    Milošević Velibor

    2014-05-01

    Full Text Available Since reserve requirement is the only monetary policy instrument used in Montenegro, it has been subject to frequent amendments since the global crisis outbreak. The analysis of the monetary demand model showed that there is an active transmission mechanism of change in the reserve requirement rate on the deposits trend reflects on lending activity. Also, there is a significant impact of FDIs on deposits trending in the banking system, as well as the positive impact of turnover on stock exchange on the deposits and loans trend. Finally, it was found that the financial crisis has caused negative trends in loans and deposits. On the other hand, the impact of changes in the reserve requirement on the economic activity in Montenegro could not be determined. This is primarily due to the fact that the transmission mechanism of the effect of reserve requirement on economic activity is too long to be able to estimate the model that does not allow the dynamics of the independent variables. The second reason is that industrial output index is only an indirect indicator of the economic activity.

  18. Reserve requirements and double Bertrand competition among banks

    NARCIS (Netherlands)

    Toolsema-Veldman, Linda

    The paper considers a model of double Bertrand competition among banks, in which banks compete for deposits as well as loans. It is shown that the introduction of reserve requirements can have an effect on the existence and efficiency properties of Nash equilibria of this model. This provides a new

  19. New approach for strategic bidding of Gencos in energy and spinning reserve markets

    International Nuclear Information System (INIS)

    Soleymani, S.; Ranjbar, A.M.; Shirani, A.R.

    2007-01-01

    In restructured and de-regulated power systems, generating companies (Gencos) are responsible for supplying electricity for both energy and reserve markets, which usually operate simultaneously. In this condition, the question is how much and for what price must each Genco generate for each market to maximize its profit, so this paper intends to answer to this question. In this paper, first, the combined energy and reserve markets are considered, and the Nash equilibrium points are determined. Then, the bidding strategies for each Genco at these points will be presented. The bids for the energy and 10 min spinning reserve (TMSR) markets are separated in the second stage, and again, the bidding strategies for each Genco for the two separated markets will be demonstrated. Comparison of the results shows that the separated bidding strategies, while being simplified with the algebraic optimization model and reducing the time consumed, give the same results as the combined ones. The Western System Coordinating Council (WSCC) nine bus test system is employed to illustrate and verify the results of the proposed method

  20. 7 CFR 985.57 - Reserve pool requirements.

    Science.gov (United States)

    2010-01-01

    ... shall be paid by the equity holders. The proceeds from the disposition of reserve oil shall be... HANDLING OF SPEARMINT OIL PRODUCED IN THE FAR WEST Order Regulating Handling Volume Limitations § 985.57... the Secretary may establish, the Committee shall pool identified excess oil as reserve oil in such...

  1. 76 FR 64250 - Reserve Requirements of Depository Institutions: Reserves Simplification and Private Sector...

    Science.gov (United States)

    2011-10-18

    ... Simplification and Private Sector Adjustment Factor AGENCY: Board of Governors of the Federal Reserve System... comment on several issues related to the methodology used for the Private Sector Adjustment Factor that is... Analyst (202) 452- 3674, Division of Monetary Affairs, or, for questions regarding the Private Sector...

  2. 12 CFR 204.5 - Maintenance of required reserves.

    Science.gov (United States)

    2010-01-01

    ... and Other Items by Federal Reserve Banks and Funds Transfers Through Fedwire” (12 CFR part 210). If a... collected funds. (d)(1) A depository institution, a U.S. branch or agency of a foreign bank, or an Edge or... institutions are Federal Home Loan Banks, the National Credit Union Administration Central Liquidity Facility...

  3. Changes in Reserve Requirements and Brazilian Banks' Stocks

    Directory of Open Access Journals (Sweden)

    Bruno De Lorenzi Cancelier Mazzucco

    2013-09-01

    Full Text Available In this study we tested the hypothesis that part of reserve requirements’ costs is paid by banks’ stockholders, instead of only by depositors and borrowers. Through an event study of fourteen regulatory changes between 1998 and 2010, we investigated the existence of abnormal returns. The results suggest that stockholders share the costs.

  4. Postextrasystolic potentiation and contractile reserve: requirements and restrictions.

    Science.gov (United States)

    Lust, R M; Lutherer, L O; Gardner, M E; Cooper, M W

    1982-12-01

    These studies were conducted to examine the basic characteristics of postextrasystolic potentiation (PESP) and the relationship of loading effects to PESP. Measurements of left ventricular (LV) and aortic pressures, the rate of pressure rise, and echocardiographically determined LV dimensions were made in anesthetized open-chest dogs. The hearts were paced, and timed extrasystoles were introduced that were followed by postextrasystoles (PES). PES's were elicited after an interval equal to either a full compensatory pause or a time when the diastolic properties of the LV could not be distinguished from control (isolength). Potentiation of contraction for the PES's introduced after an isolength pause was dependent on both the heart rate and the extrasystolic interval, whereas the PES's that occurred after a full pause showed no dependence on either of these intervals. PESP elicited during the isolength period was not dependent on either preload and afterload. It is concluded that PESP depends on the combination of heart rate and extrasystolic and postextrasystolic intervals. Further, PESP may be inaccurate in assessing contractile reserve unless the heart rate and extrasystolic interval are known and the PES is introduced after an isolength pause.

  5. Did Doubling Reserve Requirements Cause the Recession of 1937-1938? A Microeconomic Approach

    OpenAIRE

    Charles W. Calomiris; Joseph Mason; David Wheelock

    2011-01-01

    In 1936-37, the Federal Reserve doubled the reserve requirements imposed on member banks. Ever since, the question of whether the doubling of reserve requirements increased reserve demand and produced a contraction of money and credit, and thereby helped to cause the recession of 1937-1938, has been a matter of controversy. Using microeconomic data to gauge the fundamental reserve demands of Fed member banks, we find that despite being doubled, reserve requirements were not binding on bank re...

  6. THE EFFECT OF CHANGES IN RESERVE REQUIREMENTS DURING THE 1930s:

    OpenAIRE

    Thomas Mayer; Thomas F. Cargill

    2004-01-01

    The differential response of cash reserves of member banks and nonmember banks not subject to the 1936-37 increase in reserve requirements is estimated to determine whether the 1937-38 recession was caused by the increase in reserve requirements. We identify 17 states that maintained constant reserve requirements from June 1934 to June 1941. While member banks increased their cash reserve ratios relative to nonmember banks, the magnitude of the adjustment is too small to have contributed to t...

  7. 40 CFR 74.17 - Application requirements for process sources. [Reserved

    Science.gov (United States)

    2010-07-01

    ... requirements for process sources. [Reserved] ... 40 Protection of Environment 16 2010-07-01 2010-07-01 false Application requirements for process sources. [Reserved] 74.17 Section 74.17 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY...

  8. Improving Deterministic Reserve Requirements for Security Constrained Unit Commitment and Scheduling Problems in Power Systems

    Science.gov (United States)

    Wang, Fengyu

    Traditional deterministic reserve requirements rely on ad-hoc, rule of thumb methods to determine adequate reserve in order to ensure a reliable unit commitment. Since congestion and uncertainties exist in the system, both the quantity and the location of reserves are essential to ensure system reliability and market efficiency. The modeling of operating reserves in the existing deterministic reserve requirements acquire the operating reserves on a zonal basis and do not fully capture the impact of congestion. The purpose of a reserve zone is to ensure that operating reserves are spread across the network. Operating reserves are shared inside each reserve zone, but intra-zonal congestion may block the deliverability of operating reserves within a zone. Thus, improving reserve policies such as reserve zones may improve the location and deliverability of reserve. As more non-dispatchable renewable resources are integrated into the grid, it will become increasingly difficult to predict the transfer capabilities and the network congestion. At the same time, renewable resources require operators to acquire more operating reserves. With existing deterministic reserve requirements unable to ensure optimal reserve locations, the importance of reserve location and reserve deliverability will increase. While stochastic programming can be used to determine reserve by explicitly modelling uncertainties, there are still scalability as well as pricing issues. Therefore, new methods to improve existing deterministic reserve requirements are desired. One key barrier of improving existing deterministic reserve requirements is its potential market impacts. A metric, quality of service, is proposed in this thesis to evaluate the price signal and market impacts of proposed hourly reserve zones. Three main goals of this thesis are: 1) to develop a theoretical and mathematical model to better locate reserve while maintaining the deterministic unit commitment and economic dispatch

  9. 12 CFR 208.35 - Qualification requirements for transactions in certain securities. [Reserved

    Science.gov (United States)

    2010-01-01

    ... requirements for transactions in certain securities. [Reserved] ... 12 Banks and Banking 2 2010-01-01 2010-01-01 false Qualification requirements for transactions in certain securities. [Reserved] 208.35 Section 208.35 Banks and Banking FEDERAL RESERVE SYSTEM BOARD OF...

  10. 21 CFR 111.465 - What requirements apply to holding reserve samples of dietary supplements?

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 2 2010-04-01 2010-04-01 false What requirements apply to holding reserve samples... Distributing § 111.465 What requirements apply to holding reserve samples of dietary supplements? (a) You must hold reserve samples of dietary supplements in a manner that protects against contamination and...

  11. 21 CFR 111.83 - What are the requirements for reserve samples?

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 2 2010-04-01 2010-04-01 false What are the requirements for reserve samples? 111..., PACKAGING, LABELING, OR HOLDING OPERATIONS FOR DIETARY SUPPLEMENTS Requirement to Establish a Production and Process Control System § 111.83 What are the requirements for reserve samples? (a) You must collect and...

  12. Modeling of GE Appliances: Cost Benefit Study of Smart Appliances in Wholesale Energy, Frequency Regulation, and Spinning Reserve Markets

    Energy Technology Data Exchange (ETDEWEB)

    Fuller, Jason C.; Parker, Graham B.

    2012-12-31

    This report is the second in a series of three reports describing the potential of GE’s DR-enabled appliances to provide benefits to the utility grid. The first report described the modeling methodology used to represent the GE appliances in the GridLAB-D simulation environment and the estimated potential for peak demand reduction at various deployment levels. The third report will explore the technical capability of aggregated group actions to positively impact grid stability, including frequency and voltage regulation and spinning reserves, and the impacts on distribution feeder voltage regulation, including mitigation of fluctuations caused by high penetration of photovoltaic distributed generation. In this report, a series of analytical methods were presented to estimate the potential cost benefit of smart appliances while utilizing demand response. Previous work estimated the potential technical benefit (i.e., peak reduction) of smart appliances, while this report focuses on the monetary value of that participation. The effects on wholesale energy cost and possible additional revenue available by participating in frequency regulation and spinning reserve markets were explored.

  13. Inflation Targeting and Quantitative Tightening: Effects of Reserve Requirements in Peru

    OpenAIRE

    Adrián Armas; Paul Castillo; Marco Vega

    2014-01-01

    This paper provides an overview of the reserve requirement measures undertaken by the Central Bank of Peru. It provides a rationale for the use of these instruments as well as empirical evidence of their effectiveness. In general, the results show that tightening reserve requirements has the desired effects on interest rates and credit levels at both banks and smaller financial institutions (cajas municipales).

  14. 13 CFR 120.847 - Requirements for the Loan Loss Reserve Fund (LLRF).

    Science.gov (United States)

    2010-01-01

    ... Requirements for the Loan Loss Reserve Fund (LLRF). (a) General. PCLP CDCs must establish and maintain a LLRF... 13 Business Credit and Assistance 1 2010-01-01 2010-01-01 false Requirements for the Loan Loss Reserve Fund (LLRF). 120.847 Section 120.847 Business Credit and Assistance SMALL BUSINESS ADMINISTRATION...

  15. 26 CFR 1.411(d)-1 - Coordination of vesting and discrimination requirements. [Reserved

    Science.gov (United States)

    2010-04-01

    ... 26 Internal Revenue 5 2010-04-01 2010-04-01 false Coordination of vesting and discrimination requirements. [Reserved] 1.411(d)-1 Section 1.411(d)-1 Internal Revenue INTERNAL REVENUE SERVICE, DEPARTMENT OF... Plans, Etc. § 1.411(d)-1 Coordination of vesting and discrimination requirements. [Reserved] ...

  16. 26 CFR 1.6031(b)-2T - REMIC reporting requirements (temporary). [Reserved

    Science.gov (United States)

    2010-04-01

    ... requirements (temporary). [Reserved] ... 26 Internal Revenue 13 2010-04-01 2010-04-01 false REMIC reporting requirements (temporary). [Reserved] 1.6031(b)-2T Section 1.6031(b)-2T Internal Revenue INTERNAL REVENUE SERVICE, DEPARTMENT OF THE...

  17. Determining reserve requirements in DK1 area of Nord Pool using a probabilistic approach

    DEFF Research Database (Denmark)

    Saez Gallego, Javier; Morales González, Juan Miguel; Madsen, Henrik

    2014-01-01

    a probabilistic framework where the reserve requirements are computed based on scenarios of wind power forecast error, load forecast errors and power plant outages. Our approach is first motivated by the increasing wind power penetration in power systems worldwide as well as the current market design of the DK1...... System Operator). © 2014 Elsevier Ltd. All rights reserved....

  18. Optimal Bidding Strategy of Generation Companies (GenCos in Energy and Spinning Reserve Markets Using Linear Programming

    Directory of Open Access Journals (Sweden)

    Hassan Barati

    2011-10-01

    Full Text Available In this paper a new bidding strategy become modeling to day-ahead markets. The proposed algorithm is related to the point of view of a generation company (Genco that its end is maximized its benefit as a participant in sale markets of active power and spinning reserve. In this method, hourly forecasted energy price (FEP and forecasted reserve price (FRP is used as a reference to model the possible and probable price strategies of Gencos. A bi-level optimization problem That first level, is used to maximize the individual Genco’s payoffs for obtaining the optimal offered quantity of Gencos. The second one, uses the results of the upper sub-problem and minimizes the consumer’s payment with regard to the technical and network constraints, which leads to the awarded generation of the Gencos. In this paper use of the game theory in exist optimization model. The paper proposes a linear programming approach. A six bus system is employed to illustrate the application of the proposed method and to show its high precision and capabilities.

  19. Reduction of wind power induced reserve requirements by advanced shortest-term forecasts and prediction intervals

    Energy Technology Data Exchange (ETDEWEB)

    Dobschinski, Jan; Wessel, Arne; Lange, Bernhard; Bremen, Lueder von [Fraunhofer Institut fuer Windenergie und Energiesystemtechnik (IWES), Kassel (Germany)

    2009-07-01

    In electricity systems with large penetration of wind power, the limited predictability of the wind power generation leads to an increase in reserve and balancing requirements. At first the present study concentrates on the capability of dynamic day-ahead prediction intervals to reduce the wind power induced reserve and balancing requirements. Alternatively the reduction of large forecast errors of the German wind power generation by using advanced shortest-term predictions has been evaluated in a second approach. With focus on the allocation of minute reserve power the aim is to estimate the maximal remaining uncertainty after trading activities on the intraday market. Finally both approaches were used in a case study concerning the reserve requirements induced by the total German wind power expansion in 2007. (orig.)

  20. Day-ahead optimal dispatch for wind integrated power system considering zonal reserve requirements

    International Nuclear Information System (INIS)

    Liu, Fan; Bie, Zhaohong; Liu, Shiyu; Ding, Tao

    2017-01-01

    Highlights: • Analyzing zonal reserve requirements for wind integrated power system. • Modeling day-ahead optimal dispatch solved by chance constrained programming theory. • Determining optimal zonal reserve demand with minimum confidence interval. • Analyzing numerical results on test and large-scale real-life power systems. - Abstract: Large-scale integration of renewable power presents a great challenge for day-ahead dispatch to manage renewable resources while provide available reserve for system security. Considering zonal reserve is an effective way to ensure reserve deliverability when network congested, a random day-ahead dispatch optimization of wind integrated power system for a least operational cost is modeled including zonal reserve requirements and N − 1 security constraints. The random model is transformed into a deterministic one based on the theory of chance constrained programming and a determination method of optimal zonal reserve demand is proposed using the minimum confidence interval. After solving the deterministic model, the stochastic simulation is conducted to verify the validity of solution. Numerical tests and results on the IEEE 39 bus system and a large-scale real-life power system demonstrate the optimal day-ahead dispatch scheme is available and the proposed method is effective for improving reserve deliverability and reducing load shedding after large-capacity power outage.

  1. Approaches to Formation of Technical Reserves of Insurance Organizations: Domestic Realities and International Requirements

    Directory of Open Access Journals (Sweden)

    Prykaziuk Natalia V.

    2017-03-01

    Full Text Available he aim of the article is to study approaches to formation of insurance reserves by insurance companies in Ukraine and the world. The essence and peculiarities of the formation of reserves by insurance organizations in Ukraine are investigated. The provisions of the Solvency II Directive in terms of formation of reserves and financial stability in insurance organizations are considered. A comparative characteristic of the requirements for the solvency of insurers in accordance with the legislation of Ukraine and the requirements of Solvency II is presented. Differences in methods of formation of technical reserves by insurance organizations in Ukraine and the world are determined, factors affecting it are indicated. Methods of formation of insurance reserves in the countries of the European Union are considered. The directions of improving the process of formation of insurance reserves of the insurer are justified. The problems of introducing the experience of foreign countries and Solvency II requirements are analyzed taking into account the realities of the domestic insurance market. The strengths and weaknesses of the introduction of Solvency II in the Ukrainian insurance market are explored.

  2. Required sample size for monitoring stand dynamics in strict forest reserves: a case study

    Science.gov (United States)

    Diego Van Den Meersschaut; Bart De Cuyper; Kris Vandekerkhove; Noel Lust

    2000-01-01

    Stand dynamics in European strict forest reserves are commonly monitored using inventory densities of 5 to 15 percent of the total surface. The assumption that these densities guarantee a representative image of certain parameters is critically analyzed in a case study for the parameters basal area and stem number. The required sample sizes for different accuracy and...

  3. Legal Reserve Requirements in Brazilian Forests: Path Dependent Evolution of De Facto Legislation

    OpenAIRE

    Lee J. Alston; Bernardo Mueller

    2007-01-01

    Why would a poor and largely pro-developmental country such as Brazil, that has so much of its territory covered in forest, adopt one of the most restrictive land use requirements in the world when it comes to cutting the forest to give way to other economic uses? We describe the evolution of legal reserve legislation in Brazil, which currently requires that 20% of the area in a property (80% in the Amazon) be left in forest or its native vegetation. This legislation was put into place in 193...

  4. THE IMPLEMENTATION OF EFFICIENT TRADE MATRIX AND GOLD RESERVE REQUIREMENT FOR COMMODITY TRADE AMONG ASEAN COUNTRIES

    OpenAIRE

    nurul anisak

    2017-01-01

    Objective - This study attempts to implement the efficient trade matrix among five selected ASEAN countries and its settlement by the gold reserve requirements through Multi-Bilateral Payments Arrangement (MBPA).Methods – The study is a qualitative research with analytic description. The purpose of this qualitative-descriptive study is to simulate the implementation of gold in the Multi-Bilateral Payment Arrangement among ASEAN countries using the current trade data.Results – This paper argue...

  5. 17 CFR 270.27d-1 - Reserve requirements for principal underwriters and depositors to carry out the obligations to...

    Science.gov (United States)

    2010-04-01

    ... 17 Commodity and Securities Exchanges 3 2010-04-01 2010-04-01 false Reserve requirements for....27d-1 Reserve requirements for principal underwriters and depositors to carry out the obligations to... reserve and as security for the purpose of assuring the refund of charges required by sections 27(d) and...

  6. THE IMPLEMENTATION OF EFFICIENT TRADE MATRIX AND GOLD RESERVE REQUIREMENT FOR COMMODITY TRADE AMONG ASEAN COUNTRIES

    Directory of Open Access Journals (Sweden)

    nurul anisak

    2017-06-01

    Full Text Available Objective - This study attempts to implement the efficient trade matrix among five selected ASEAN countries and its settlement by the gold reserve requirements through Multi-Bilateral Payments Arrangement (MBPA.Methods – The study is a qualitative research with analytic description. The purpose of this qualitative-descriptive study is to simulate the implementation of gold in the Multi-Bilateral Payment Arrangement among ASEAN countries using the current trade data.Results – This paper argues that the Southeast Asian countries can solve the problem through their internal coordination, particularly in terms of trade. One of the efforts is to reduce even eliminate the market risk by using the efficient payment arrangement.Conclusions – The study implied that the quantity amount of gold required to settle the trade balance will be reduced from the early gross payment. However, the ASEAN countries need to strengthen the cooperation among them through maximizing the trade relationship.

  7. [Energy requirements in adolescents playing basketball in Russian Olympic reserve team].

    Science.gov (United States)

    Martinchik, A N; Baturin, A K; Petukhov, A B; Baeva, V S; Zemlianskaia, T A; Sokolov, A I; Peskova, E V; Tysiachnaia, E M

    2003-01-01

    The energy expenditure and requirements and dietary intake were studied in basketball players aged 14-16 years during 3 week-training period. The subjects of study were 14 boys and 18 girls as of the members of reserve of Russian Olympic basketball team. The dietary intake was estimated by dietary record of all food consumed within 24 hours last 7 days of training period. The energy expenditure was estimated by registration of time on different physical activity of team and multiplication on physical activity coefficient. The decrease of body mass and body mass index were observed in boys with height 195 cm and more to the end of training period. These tall boys did not consume enough food to satisfy the estimated energy requirement. It is estimated that energy need of tall basketball players is no less then 5000 kcal for boys and 3100 kcal for girls.

  8. Power system reliability impacts of wind generation and operational reserve requirements

    Directory of Open Access Journals (Sweden)

    Esteban Gil

    2015-06-01

    Full Text Available Due to its variability, wind generation integration presents a significant challenge to power system operators in order to maintain adequate reliability levels while ensuring least cost operation. This paper explores the trade-off between the benefits associated to a higher wind penetration and the additional operational reserve requirements that they impose. Such exploration is valued in terms of its effect on power system reliability, measured as an amount of unserved energy. The paper also focuses on how changing the Value of Lost Load (VoLL can be used to attain different reliability targets, and how wind power penetration and the diversity of the wind energy resource will impact quality of supply (in terms of instances of unserved energy. The evaluation of different penetrations of wind power generation, different wind speed profiles, wind resource diversity, and different operational reserve requirements, is conducted on the Chilean Northern Interconnected System (SING using statistical modeling of wind speed time series and computer simulation through a 24-hour ahead unit commitment algorithm and a Monte Carlo simulation scheme. Results for the SING suggest that while wind generation can significantly reduce generation costs, it can also imply higher security costs to reach acceptable reliability levels.

  9. The Impact of the Required Reserve on the Monetary Multiplication in the Republic of Macedonias

    Directory of Open Access Journals (Sweden)

    Aleksandar Dejanovski

    2014-11-01

    Full Text Available One of the primary and most important tasks of any central bank is conducting monetary policy in the state. In Macedonia the only central and issuing bank is the National Bank of Macedonia, which is responsible for the monetary and financial stability in the country, while performing important functions, without which the overall economic and financial system could not exist. In exercising its functions, the National Bank of Macedonia uses a set of economic instruments and policies, from which in RM the most efective is the required resserve. This monetary tool is showing the best results in developing countries where the financial markets are not developed and where there is a high concentration of the banking sector (in RM banks occupy a good 98% of total financial institutions. The role of the reserve will be analyzed through the prism of its effects on the process of multiplication the money supply in the country and its contribution to generating or withdrawal of money by the central bank. The main goal of the paper is to research the required reserve, as a monetary instrument, and to qualify its impact on the monetary creation in the Republic of Macedonia. The basic methods, used in this paper are the positive analysis, comparative analysis and deductive approach.

  10. Arabidopsis plastidial folylpolyglutamate synthetase is required for seed reserve accumulation and seedling establishment in darkness.

    Directory of Open Access Journals (Sweden)

    Hongyan Meng

    Full Text Available Interactions among metabolic pathways are important in plant biology. At present, not much is known about how folate metabolism affects other metabolic pathways in plants. Here we report a T-DNA insertion mutant (atdfb-3 of the plastidial folylpolyglutamate synthetase gene (AtDFB was defective in seed reserves and skotomorphogenesis. Lower carbon (C and higher nitrogen (N content in the mutant seeds than that of the wild type were indicative of an altered C and N partitioning capacity. Higher levels of organic acids and sugars were detected in the mutant seeds compared with the wild type. Further analysis revealed that atdfb-3 seeds contained less total amino acids and individual Asn and Glu as well as NO3-. These results indicate significant changes in seed storage in the mutant. Defects in hypocotyl elongation were observed in atdfb-3 in darkness under sufficient NO3- conditions, and further enhanced under NO3- limited conditions. The strong expression of AtDFB in cotyledons and hypocotyl during early developmental stage was consistent with the mutant sensitivity to limited NO3- during a narrow developmental window. Exogenous 5-formyl-tetrahydrofolate completely restored the hypocotyl length in atdfb-3 seedlings with NO3- as the sole N source. Further study demonstrated that folate profiling and N metabolism were perturbed in atdfb-3 etiolated seedlings. The activity of enzymes involved in N reduction and assimilation was altered in atdfb-3. Taken together, these results indicate that AtDFB is required for seed reserves, hypocotyl elongation and N metabolism in darkness, providing novel insights into potential associations of folate metabolism with seed reserve accumulation, N metabolism and hypocotyl development in Arabidopsis.

  11. Requirement for Naval Reserve Component Units Not Assigned to Support Regional Contingencies

    National Research Council Canada - National Science Library

    Gimble, Thomas

    1996-01-01

    Our primary objective was to determine whether a valid need exists for Naval Reserve units and non-unit Reserve personnel who are not assigned to meet the needs of anticipated regional contingencies...

  12. 12 CFR 204.136 - Treatment of trust overdrafts for reserve requirement reporting purposes.

    Science.gov (United States)

    2010-01-01

    ... accounts under Regulation D. Unless the governing trust agreement or state law authorizes the depository... pursuant to trust law or written agreement, or where the amount that caused the overdraft is still... 12 Banks and Banking 2 2010-01-01 2010-01-01 false Treatment of trust overdrafts for reserve...

  13. Modeling the Anomalous Microwave Emission with Spinning Nanoparticles: No PAHs Required

    Energy Technology Data Exchange (ETDEWEB)

    Hensley, Brandon S. [Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, CA 91109 (United States); Draine, B. T., E-mail: brandon.s.hensley@jpl.nasa.gov [Department of Astrophysical Sciences, Princeton University, Princeton, NJ 08544 (United States)

    2017-02-20

    In light of recent observational results indicating an apparent lack of correlation between the anomalous microwave emission (AME) and mid-infrared emission from polycyclic aromatic hydrocarbons, we assess whether rotational emission from spinning silicate and/or iron nanoparticles could account for the observed AME without violating observational constraints on interstellar abundances, ultraviolet extinction, and infrared emission. By modifying the SpDust code to compute the rotational emission from these grains, we find that nanosilicate grains could account for the entirety of the observed AME, whereas iron grains could be responsible for only a fraction, even for extreme assumptions on the amount of interstellar iron concentrated in ultrasmall iron nanoparticles. Given the added complexity of contributions from multiple grain populations to the total spinning dust emission, as well as existing uncertainties due to the poorly constrained grain size, charge, and dipole moment distributions, we discuss generic, carrier-independent predictions of spinning dust theory and observational tests that could help identify the AME carrier(s).

  14. Mentha spicata L. infusions as sources of antioxidant phenolic compounds: emerging reserve lots with special harvest requirements.

    Science.gov (United States)

    Rita, Ingride; Pereira, Carla; Barros, Lillian; Santos-Buelga, Celestino; Ferreira, Isabel C F R

    2016-10-12

    Mentha spicata L., commonly known as spearmint, is widely used in both fresh and dry forms, for infusion preparation or in European and Indian cuisines. Recently, with the evolution of the tea market, several novel products with added value are emerging, and the standard lots have evolved to reserve lots, with special harvest requirements that confer them with enhanced organoleptic and sensorial characteristics. The apical leaves of these batches are collected in specific conditions having, then, a different chemical profile. In the present study, standard and reserve lots of M. spicata were assessed in terms of the antioxidants present in infusions prepared from the different lots. The reserve lots presented the highest concentration in all the compounds identified in relation to the standard lots, with 326 and 188 μg mL -1 of total phenolic compounds, respectively. Both types of samples presented rosmarinic acid as the most abundant phenolic compound, at concentrations of 169 and 101 μg mL -1 for reserve and standard lots, respectively. The antioxidant activity was higher in the reserve lots which had the highest total phenolic compounds content, with EC 50 values ranging from 152 to 336 μg mL -1 . The obtained results provide scientific information that may allow the consumer to make a conscientious choice.

  15. 31 CFR 363.28 - Does Public Debt reserve the right to require that any TreasuryDirect ® transaction be conducted...

    Science.gov (United States)

    2010-07-01

    ... 31 Money and Finance: Treasury 2 2010-07-01 2010-07-01 false Does Public Debt reserve the right to... Provisions Governing Securities Held in TreasuryDirect § 363.28 Does Public Debt reserve the right to require that any TreasuryDirect ® transaction be conducted in paper form? We reserve the right to require any...

  16. JAK/STAT-1 Signaling Is Required for Reserve Intestinal Stem Cell Activation during Intestinal Regeneration Following Acute Inflammation

    Directory of Open Access Journals (Sweden)

    Camilla A. Richmond

    2018-01-01

    Full Text Available The intestinal epithelium serves as an essential barrier to the outside world and is maintained by functionally distinct populations of rapidly cycling intestinal stem cells (CBC ISCs and slowly cycling, reserve ISCs (r-ISCs. Because disruptions in the epithelial barrier can result from pathological activation of the immune system, we sought to investigate the impact of inflammation on ISC behavior during the regenerative response. In a murine model of αCD3 antibody-induced small-intestinal inflammation, r-ISCs proved highly resistant to injury, while CBC ISCs underwent apoptosis. Moreover, r-ISCs were induced to proliferate and functionally contribute to intestinal regeneration. Further analysis revealed that the inflammatory cytokines interferon gamma and tumor necrosis factor alpha led to r-ISC activation in enteroid culture, which could be blocked by the JAK/STAT inhibitor, tofacitinib. These results highlight an important role for r-ISCs in response to acute intestinal inflammation and show that JAK/STAT-1 signaling is required for the r-ISC regenerative response.

  17. Reform of reserve requirements for nuclear decommissioning, dismantling and disposal; Reform der Atomrueckstellungen fuer Stilllegung/Rueckbau und Entsorgung

    Energy Technology Data Exchange (ETDEWEB)

    Meyer, Bettina [Forum Oekologisch-Soziale Marktwirtschaft e.V. (FOeS), Berlin (Germany); Kuechler, Swantje; Wronski, Rupert [Forum Oekologisch-Soziale Marktwirtschaft e.V. (FOeS), Berlin (Germany). Bereich Energiepolitik

    2015-07-15

    This article reports on the ongoing intense discussion as to whether the financial reserves of nuclear power plant operators are sufficient. It starts out with an overview of the current scientific and political debate. This is followed by a brief analysis of nuclear financial reserves in 2014 and preceding years. The authors then present the reform concept of the Forum Oekologisch-Soziale Marktwirtschaft (FOes) and go on to compare it with concepts from the political realm.

  18. Federal and state permits required to open a new uranium mine with comments on uranium development on Indian reservations

    International Nuclear Information System (INIS)

    Root, T.E.; Whisler, J.S.

    1976-01-01

    Three federally related problems are discussed: the environmental impact statement, water discharge permits, and access. A cookbook approach to the permitting process is given as it exists in Wyoming, Utah, New Mexico, and Arizona. The question of jurisdiction is dealt with by using a case study approach to illustrate how jurisdiction bears on uranium development on Indian reservations

  19. Spin-4 extended conformal algebras

    International Nuclear Information System (INIS)

    Kakas, A.C.

    1988-01-01

    We construct spin-4 extended conformal algebras using the second hamiltonian structure of the KdV hierarchy. In the presence of a U(1) current a family of spin-4 algebras exists but the additional requirement that the spin-1 and spin-4 currents commute fixes the algebra uniquely. (orig.)

  20. Spin nematics next to spin singlets

    Science.gov (United States)

    Yokoyama, Yuto; Hotta, Chisa

    2018-05-01

    We provide a route to generate nematic order in a spin-1/2 system. Unlike the well-known magnon-binding mechanism, our spin nematics requires neither the frustration effect nor spin polarization in a high field or in the vicinity of a ferromagnet, but instead appears next to the spin singlet phase. We start from a state consisting of a quantum spin-1/2 singlet dimer placed on each site of a triangular lattice, and show that interdimer ring exchange interactions efficiently dope the SU(2) triplets that itinerate and interact, easily driving a stable singlet state to either Bose-Einstein condensates or a triplet crystal, some hosting a spin nematic order. A variety of roles the ring exchange serves includes the generation of a bilinear-biquadratic interaction between nearby triplets, which is responsible for the emergent nematic order separated from the singlet phase by a first-order transition.

  1. Coordinated Early Intervening Services: Programs in Local Education Agencies that Are Required to Reserve IDEA Funds. inForum

    Science.gov (United States)

    Burdette, Paula; Sopko, Kimberly Moherek

    2010-01-01

    Disproportionate representation of children from diverse racial and ethnic backgrounds in special education has been a longstanding concern that the 2004 reauthorization of the Individuals with Disabilities Education Act (IDEA) sought to address. The IDEA contains new requirements related to the provision of early intervening services designed to…

  2. Policy Decisions With Regard To The Applicability Of The Clean Air Act Requirements To The Strategic Petroleum Reserve

    Science.gov (United States)

    This document may be of assistance in applying the New Source Review (NSR) air permitting regulations including the Prevention of Significant Deterioration (PSD) requirements. This document is part of the NSR Policy and Guidance Database. Some documents in the database are a scanned or retyped version of a paper photocopy of the original. Although we have taken considerable effort to quality assure the documents, some may contain typographical errors. Contact the office that issued the document if you need a copy of the original.

  3. Efficient Spin Injection into Semiconductor

    International Nuclear Information System (INIS)

    Nahid, M.A.I.

    2010-06-01

    Spintronic research has made tremendous progress nowadays for making future devices obtain extra advantages of low power, and faster and higher scalability compared to present electronic devices. A spintronic device is based on the transport of an electron's spin instead of charge. Efficient spin injection is one of the very important requirements for future spintronic devices. However, the effective spin injection is an exceedingly difficult task. In this paper, the importance of spin injection, basics of spin current and the essential requirements of spin injection are illustrated. The experimental technique of electrical spin injection into semiconductor is also discussed based on the experimental experience. The electrical spin injection can easily be implemented for spin injection into any semiconductor. (author)

  4. [Modeling of the financial reserves required by the livestock disease compensation fund of Lower Saxony for rebates in the course of disease outbreaks incorporating spatial restriction zones].

    Science.gov (United States)

    Denzin, Nicolai; Gerdes, Ursula

    2015-01-01

    One of the tasks of the livestock disease compensation funds of the federal states in Germany is the financial compensation of livestock holders for livestock losses and costs incurred for disease control measures due to certain diseases. Usually, one half of these services are financed through financial reserves built up with the contributions paid by the owners of the respective animal species. The other half is covered by the federal state itself. But there is hardly any reference to how to calculate aforementioned financial reserves. Basically, following an approach presented recently regarding estimations concerning the compensation fund of the federal state of Saxony-Anhalt, in a stochastic modeling of the required reserves concerning the fund of Lower Saxony the anticipated costs within the spatial restriction zones allocated to outbreaks were incorporated for the first time. The overall costs (including the federal state's stakes), the share of the comnensation fund (required reserves) and the the partial costs for a total of 25 categories and subcategories and subcategories of livestock species making up the latter were estimated. It became evident that overall costs/the share of the fund were particularly determined among the diseases by foot-and-mouth disease and among the cost factors by the costs incurred for the compensation of livestock value within the areas surrounding the outbreaks in which all susceptible animals are killed (culling zone). The 80th, 90 and 95th percentile of the established probability distribution of the overall costs referred to a financial volume of about 312, 409 and 540 million euro, while the respective percentiles of the probability distribution of the required reserves of the compensation fund amounted to 175, 225 and 296 million euro.

  5. Spin current

    CERN Document Server

    Valenzuela, Sergio O; Saitoh, Eiji; Kimura, Takashi

    2012-01-01

    In a new branch of physics and technology called spin-electronics or spintronics, the flow of electrical charge (usual current) as well as the flow of electron spin, the so-called 'spin current', are manipulated and controlled together. This book provides an introduction and guide to the new physics and application of spin current.

  6. A Mathematical Model and Programme Support for Determination of the Values of the Marginal Reserve Requirement as Instrument of Monetary Policy

    Directory of Open Access Journals (Sweden)

    Kristina Šorić

    2007-09-01

    Full Text Available This paper studies the problem of interdependence between central bank and commercial bank goals. The basic central bank task is to achieve and to maintain price stability. Croatian external debt has been increasing for years and so the activities of the Croatian National Bank are designed to correct this situation. In order to stop the further increase of the external debt, the Croatian National Bank uses several monetary policy instruments, among which is the marginal reserve requirement. On the other hand, the goal of commercial banks is to maximise profits. Banks take loans from abroad at a lower interest rate and invest this money in Croatia at a higher interest rate, thus fulfilling their goal. In order to obtain the desired effects of the marginal reserve requirement, its optimal percentage value should be determined. This problem is modelled as a bi-level mixed 0-1 programming problem. The objective of the leader (Croatian National Bank is to minimize the increase in household loans by setting different percentages of the reserve requirements for loans extended to households and for those granted to enterprises. The objective of the followers (banks is to maximize profits. In order to solve this NP-hard problem a heuristic is proposed. In order to verify the model, the paper ends with simulations and the presentation of computational results.

  7. RESEARCH PLAN FOR SPIN PHYSICS AT RHIC.

    Energy Technology Data Exchange (ETDEWEB)

    AIDALA, C.; BUNCE, G.; ET AL.

    2005-02-01

    In this report we present the research plan for the RHIC spin program. The report covers (1) the science of the RHIC spin program in a world-wide context; (2) the collider performance requirements for the RHIC spin program; (3) the detector upgrades required, including timelines; (4) time evolution of the spin program.

  8. Geometrical spin symmetry and spin

    International Nuclear Information System (INIS)

    Pestov, I. B.

    2011-01-01

    Unification of General Theory of Relativity and Quantum Mechanics leads to General Quantum Mechanics which includes into itself spindynamics as a theory of spin phenomena. The key concepts of spindynamics are geometrical spin symmetry and the spin field (space of defining representation of spin symmetry). The essence of spin is the bipolar structure of geometrical spin symmetry induced by the gravitational potential. The bipolar structure provides a natural derivation of the equations of spindynamics. Spindynamics involves all phenomena connected with spin and provides new understanding of the strong interaction.

  9. What's an ARAR?exclamation point: Regulatory requirements for CERCLA remedial activities at D ampersand D sites on the Oak Ridge Reservation

    International Nuclear Information System (INIS)

    Houlberg, L.M.; Etnier, E.L.

    1994-01-01

    Many government-owned facilities that supported early nuclear energy research and defense programs have no current use and have been retired. Some of these facilities have residual radioactive or chemical contamination that require remediation. The Department of Energy (DOE) Decontamination and Decommissioning (D ampersand D) Program is responsible for managing these surplus facilities. Remedial activities for contaminated environs and inactive land-based units (e.g., landfills, surface impoundments) at the Oak Ridge Reservation (ORR) are conducted under the direction of the Environmental Restoration (ER) Program

  10. Compliance with the Clean Air Act Title VI Stratospheric Ozone Protection Program requirements at U.S. DOE Oak Ridge Reservation Facilities

    International Nuclear Information System (INIS)

    Humphreys, M.P.; Atkins, E.M.

    1999-01-01

    The Title VI Stratospheric Ozone Protection Program of the Clean Air Act (CAA) requires promulgation of regulations to reduce and prevent damage to the earth's protective ozone layer. Regulations pursuant to Title VI of the CAA are promulgated in the Code of Federal Regulations (CFR) at Title 40 CFR, Part 822. The regulations include ambitious production phaseout schedules for ozone depleting substances (ODS) including chlorofluorocarbons (CFCs), hydrochlorofluorocarbons (HCFCs), halons, carbon tetrachloride, and methyl chloroform under 40 CFR 82, Subpart A. The regulations also include requirements for recycling and emissions reduction during the servicing of refrigeration equipment and technician certification requirements under Subpart F; provisions for servicing of motor vehicle air conditioners under Subpart B; a ban on nonessential products containing Class 1 ODS under Subpart C; restrictions on Federal procurement of ODS under Subpart D; labeling of products using ODS under Subpart E; and the Significant New Alternatives Policy Program under Subpart G. This paper will provide details of initiatives undertaken at US Department of Energy (DOE) Oak Ridge Reservation (ORR) Facilities for implementation of requirements under the Title VI Stratospheric Ozone Protection Program. The Stratospheric Ozone Protection Plans include internal DOE requirements for: (1) maintenance of ODS inventories; (2) ODS procurement practices; (3) servicing of refrigeration and air conditioning equipment; (4) required equipment modifications or replacement; (5) technician certification training; (6) labeling of products containing ODS; (7) substitution of chlorinated solvents; and (8) replacement of halon fire protection systems. The plans also require establishment of administrative control systems which assure that compliance is achieved and maintained as the regulations continue to develop and become effective

  11. Spin, mass, and symmetry

    International Nuclear Information System (INIS)

    Peskin, M.E.

    1994-01-01

    When the strong interactions were a mystery, spin seemed to be just a complication on top of an already puzzling set of phenomena. But now that particle physicists have understood the strong, weak, and electromagnetic interactions, to be gauge theories, with matter built of quarks and leptons, it is recognized that the special properties of spin 1/2 and spin 1 particles have taken central role in the understanding of Nature. The lectures in this summer school will be devoted to the use of spin in unravelling detailed questions about the fundamental interactions. Thus, why not begin by posing a deeper question: Why is there spin? More precisely, why do the basic pointlike constituents of Nature carry intrinsic nonzero quanta of angular momentum? Though the authos has found no definite answer to this question, the pursuit of an answer has led through a wonderful tangle of speculations on the deep structure of Nature. Is spin constructed or is it fundamental? Is it the requirement of symmetry? In the furthest flights taken, it seems that space-time itself is too restrictive a notion, and that this must be generalized in order to gain a full appreciation of spin. In any case, there is no doubt that spin must play a central role in unlocking the mysteries of fundamental physics

  12. Spin, mass, and symmetry

    Energy Technology Data Exchange (ETDEWEB)

    Peskin, M.E. [Stanford Univ., CA (United States)

    1994-12-01

    When the strong interactions were a mystery, spin seemed to be just a complication on top of an already puzzling set of phenomena. But now that particle physicists have understood the strong, weak, and electromagnetic interactions, to be gauge theories, with matter built of quarks and leptons, it is recognized that the special properties of spin 1/2 and spin 1 particles have taken central role in the understanding of Nature. The lectures in this summer school will be devoted to the use of spin in unravelling detailed questions about the fundamental interactions. Thus, why not begin by posing a deeper question: Why is there spin? More precisely, why do the basic pointlike constituents of Nature carry intrinsic nonzero quanta of angular momentum? Though the authos has found no definite answer to this question, the pursuit of an answer has led through a wonderful tangle of speculations on the deep structure of Nature. Is spin constructed or is it fundamental? Is it the requirement of symmetry? In the furthest flights taken, it seems that space-time itself is too restrictive a notion, and that this must be generalized in order to gain a full appreciation of spin. In any case, there is no doubt that spin must play a central role in unlocking the mysteries of fundamental physics.

  13. Spinning Them Off: Entrepreneuring Practices in Corporate Spin-Offs

    Directory of Open Access Journals (Sweden)

    Katja Maria Hydle

    2016-01-01

    Full Text Available This paper focuses on the practices between parent and child firms in corporate spinoffs. We uncover the enacted aspects of knowledge, called knowing, through theories from seven cases of incumbent-backed spin-offs and find that the management of the parent firms are highly involved in the spin-offs. The practices associated with spinning off are solving problems, involving multidisciplinary expertise and entrepreneuring management at the parent firm. We contribute to the spin-off literature by discussing the knowledge required for successfully spinning off child firms and to practice theory by empirically uncovering the practical understanding involved in the origin and perpetuation of an organization.

  14. Implementation of the Clean Air Act, Title III, Section 112(r) Prevention of Accidental Release Rule requirements at U.S. DOE Oak Ridge Reservation facilities

    International Nuclear Information System (INIS)

    Humphreys, M.P.

    1997-01-01

    Title III, Section 112(r) of the Clean Air Act (CAA) Amendments of 1990 requires the Environmental Protection Agency (EPA) to promulgate regulations to prevent accidental releases of regulated substances and to reduce the severity of those releases that do occur. The final EPA rule for Risk Management Programs under Section 112(r)(7) of the CAA, promulgated June 20, 1996, applies to all stationary sources with processes that contain more than a threshold quantity of any of 139 regulated substances listed under 40 CFR 68.130. All affected sources will be required to prepare a risk management plan which must be submitted to EPA and be made available to state and local governments and to the public. This paper will provide details of initiatives underway at US Department of Energy (DOE) Oak Ridge Reservation (ORR) Facilities for implementation of the Prevention of Accidental Release Rule. The ORR encompasses three DOE Facilities: the Y-12 Plant, Oak Ridge National Laboratory (ORNL), and the K-25 Site. The Y-12 Plant manufactures component parts for the national nuclear weapons program; the ORNL is responsible for research and development activities including nuclear engineering, engineering technologies, and the environmental sciences; and the K-25 Site conducts a variety of research and development activities and is the home of a mixed waste incinerator. ORR activities underway and soon to be undertaken toward implementation of the Prevention of Accidental Release Rule include: compilation of inventories of regulated substances at all processes at each of the three ORR Facilities for determination of affected processes and facilities; plans for inventory reduction to levels below threshold quantities, where necessary and feasible; determination of the overlap of processes subject to the OSHA PSM Standard and determination of parallel requirements; preparation of Risk Management Plans and Programs for affected processes and facilities including detailed requirements

  15. Fundamental Drivers of the Cost and Price of Operating Reserves

    Energy Technology Data Exchange (ETDEWEB)

    Hummon, Marissa [National Renewable Energy Lab. (NREL), Golden, CO (United States); Denholm, Paul [National Renewable Energy Lab. (NREL), Golden, CO (United States); Jorgenson, Jennie [National Renewable Energy Lab. (NREL), Golden, CO (United States); Palchak, David [National Renewable Energy Lab. (NREL), Golden, CO (United States); Kirby, Brendan [Kirby Consultant; Ma, Ookie [U.S. Department of Energy, Washington, DC (United States)

    2013-07-01

    Operating reserves impose a cost on the electric power system by forcing system operators to keep partially loaded spinning generators available for responding to system contingencies variable demand. In many regions of the United States, thermal power plants provide a large fraction of the operating reserve requirement. Alternative sources of operating reserves, such as demand response and energy storage, may provide more efficient sources of these reserves. However, to estimate the potential value of these services, the cost of reserve services under various grid conditions must first be established. This analysis used a commercial grid simulation tool to evaluate the cost and price of several operating reserve services, including spinning contingency reserves and upward regulation reserves. These reserve products were evaluated in a utility system in the western United States, considering different system flexibilities, renewable energy penetration, and other sensitivities. The analysis demonstrates that the price of operating reserves depend highly on many assumptions regarding the operational flexibility of the generation fleet, including ramp rates and the fraction of fleet available to provide reserves.

  16. Spin current

    CERN Document Server

    Valenzuela, Sergio O; Saitoh, Eiji; Kimura, Takashi

    2017-01-01

    Since the discovery of the giant magnetoresistance effect in magnetic multilayers in 1988, a new branch of physics and technology, called spin-electronics or spintronics, has emerged, where the flow of electrical charge as well as the flow of electron spin, the so-called “spin current,” are manipulated and controlled together. The physics of magnetism and the application of spin current have progressed in tandem with the nanofabrication technology of magnets and the engineering of interfaces and thin films. This book aims to provide an introduction and guide to the new physics and applications of spin current, with an emphasis on the interaction between spin and charge currents in magnetic nanostructures.

  17. Spin doctoring

    OpenAIRE

    Vozková, Markéta

    2011-01-01

    1 ABSTRACT The aim of this text is to provide an analysis of the phenomenon of spin doctoring in the Euro-Atlantic area. Spin doctors are educated people in the fields of semiotics, cultural studies, public relations, political communication and especially familiar with the infrastructure and the functioning of the media industry. Critical reflection of manipulative communication techniques puts spin phenomenon in historical perspective and traces its practical use in today's social communica...

  18. Spin 1990

    International Nuclear Information System (INIS)

    Anton, Gisela

    1990-01-01

    The idea of the intrinsic angular momentum, or 'spin', of a particle has played an essential part in fundamental physics for more than 60 years, and its continuing importance was underlined at the 9th International Symposium on High Energy Spin Physics, held in September in Bonn.

  19. Spin 1990

    Energy Technology Data Exchange (ETDEWEB)

    Anton, Gisela

    1990-12-15

    The idea of the intrinsic angular momentum, or 'spin', of a particle has played an essential part in fundamental physics for more than 60 years, and its continuing importance was underlined at the 9th International Symposium on High Energy Spin Physics, held in September in Bonn.

  20. Spin tomography

    Energy Technology Data Exchange (ETDEWEB)

    D' Ariano, G M [Quantum Optics and Information Group, INFM Udr Pavia, Dipartimento di Fisica ' Alessandro Volta' and INFM, Via Bassi 6, 27100 Pavia (Italy); Maccone, L [Quantum Optics and Information Group, INFM Udr Pavia, Dipartimento di Fisica ' Alessandro Volta' and INFM, Via Bassi 6, 27100 Pavia (Italy); Paini, M [Quantum Optics and Information Group, INFM Udr Pavia, Dipartimento di Fisica ' Alessandro Volta' and INFM, Via Bassi 6, 27100 Pavia (Italy)

    2003-02-01

    We propose a tomographic reconstruction scheme for spin states. The experimental set-up, which is a modification of the Stern-Gerlach scheme, can be easily performed with currently available technology. The method is generalized to multiparticle states, analysing the spin-1/2 case for indistinguishable particles. Some Monte Carlo numerical simulations are given to illustrate the technique.

  1. Spin tomography

    International Nuclear Information System (INIS)

    D'Ariano, G M; Maccone, L; Paini, M

    2003-01-01

    We propose a tomographic reconstruction scheme for spin states. The experimental set-up, which is a modification of the Stern-Gerlach scheme, can be easily performed with currently available technology. The method is generalized to multiparticle states, analysing the spin-1/2 case for indistinguishable particles. Some Monte Carlo numerical simulations are given to illustrate the technique

  2. Spin glasses

    CERN Document Server

    Bovier, Anton

    2007-01-01

    Spin glass theory is going through a stunning period of progress while finding exciting new applications in areas beyond theoretical physics, in particular in combinatorics and computer science. This collection of state-of-the-art review papers written by leading experts in the field covers the topic from a wide variety of angles. The topics covered are mean field spin glasses, including a pedagogical account of Talagrand's proof of the Parisi solution, short range spin glasses, emphasizing the open problem of the relevance of the mean-field theory for lattice models, and the dynamics of spin glasses, in particular the problem of ageing in mean field models. The book will serve as a concise introduction to the state of the art of spin glass theory, usefull to both graduate students and young researchers, as well as to anyone curious to know what is going on in this exciting area of mathematical physics.

  3. Spin symposium

    Energy Technology Data Exchange (ETDEWEB)

    Anon.

    1989-01-15

    The recent 8th International Symposium on High Energy Spin Physics at the University of Minnesota in Minneapolis, Minnesota, opened with a bang when L. Pondrom (Wisconsin), donning a hard hat borrowed from construction workers, ventured that 'spin, the notorious inessential complication of hadronic physics, is finally telling us what real QCD (quantum chromodynamics, the field theory of quarks and gluons) looks like.' He was referring to an animated discussion on the meaning of the recent spin oriented (polarized) scattering results from the European Muon Collaboration (EMC) at CERN and reported at the Symposium by R. Garnet (Liverpool) and P. Schuler (Yale) which show that the proton spin is not simply a reflection of the spins of its constituent quarks.

  4. 456 Hours to Train the Reserve Component: Analysis of the Impact of Increased Annual Training Requirements on 4th Assault Amphibian Battalion

    Science.gov (United States)

    2016-12-01

    blended learning format” (p. 92). Online training can be used in the following ways: a sole source of learning , supplemental traditional, follow-up to... Learned MCI Marine Corps Institute MCO Marine Corps Order MCR Marine Corps Reserve MCTIMS Marine Corps Training Information Management System MCTL...Reserve SMCR Selected Marine Corps Reserve SNCO Staff Noncommissioned Officer SUL Small Unit Leader TAM Technology Acceptance Model TEEP Training

  5. Applicable or Relevant and Appropriate Requirements (ARARs) for Remedial Action at the Oak Ridge Reservation: A compendium of major environmental laws

    International Nuclear Information System (INIS)

    Etnier, E.L.; McDonald, E.P.; Houlberg, L.M.

    1993-07-01

    Section 121 of the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA) of 1980 specifies that remedial actions for cleanup of hazardous substances must comply with applicable or relevant and appropriate requirements (ARARS) or standards under federal and state environmental laws. The US Department of Energy (DOE) Oak Ridge Reservation (ORR) was placed on the National Priorities List by the US Environmental Protection Agency (EPA) on November 21, 1989, effective December 21, 1989. As a result of this listing, DOE, EPA, and the Tennessee Department of Environment and Conservation have signed a Federal Facility Agreement (FFA) for the environmental restoration of the ORR. Section XXI(F) of the FFA calls for the preparation of a draft listing of all ARARs as mandated by CERCLA section 121. This report supplies a preliminary list of available federal and state ARARs that might be considered for remedial response at the ORR. A description of the terms ''applicable'' and ''relevant and appropriate'' is provided, as well as definitions of chemical-, location-, and action-specific ARARS. ARARs promulgated by the federal government and by the state of Tennessee are listed in tables. In addition, the major provisions of the Resource Conservation and Recovery Act, the Safe Drinking Water Act, the Clean Water Act, the Clean Air and other acts, as they apply to hazardous waste cleanup, are discussed. In the absence of ARARS, CERCLA section 121 provides for the use of nonpromulgated federal criteria, guidelines, and advisories in evaluating the human risk associated with remedial action alternatives. Such nonpromulgated standards are classified as ''to-be-considered'' (TBC) guidance. A ion of available guidance is given; summary tables fist the available federal standards and guidance information. In addition, the substantive contents of the DOE orders as they apply to remediation of radioactively contaminated sites are discussed as TBC guidance

  6. Applicable or Relevant and Appropriate Requirements (ARARs) for Remedial Action at the Oak Ridge Reservation: A compendium of major environmental laws. Environmental Restoration Program

    Energy Technology Data Exchange (ETDEWEB)

    Etnier, E.L.; McDonald, E.P.; Houlberg, L.M.

    1993-07-01

    Section 121 of the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA) of 1980 specifies that remedial actions for cleanup of hazardous substances must comply with applicable or relevant and appropriate requirements (ARARS) or standards under federal and state environmental laws. The US Department of Energy (DOE) Oak Ridge Reservation (ORR) was placed on the National Priorities List by the US Environmental Protection Agency (EPA) on November 21, 1989, effective December 21, 1989. As a result of this listing, DOE, EPA, and the Tennessee Department of Environment and Conservation have signed a Federal Facility Agreement (FFA) for the environmental restoration of the ORR. Section XXI(F) of the FFA calls for the preparation of a draft listing of all ARARs as mandated by CERCLA {section}121. This report supplies a preliminary list of available federal and state ARARs that might be considered for remedial response at the ORR. A description of the terms ``applicable`` and ``relevant and appropriate`` is provided, as well as definitions of chemical-, location-, and action-specific ARARS. ARARs promulgated by the federal government and by the state of Tennessee are listed in tables. In addition, the major provisions of the Resource Conservation and Recovery Act, the Safe Drinking Water Act, the Clean Water Act, the Clean Air and other acts, as they apply to hazardous waste cleanup, are discussed. In the absence of ARARS, CERCLA {section}121 provides for the use of nonpromulgated federal criteria, guidelines, and advisories in evaluating the human risk associated with remedial action alternatives. Such nonpromulgated standards are classified as ``to-be-considered`` (TBC) guidance. A ion of available guidance is given; summary tables fist the available federal standards and guidance information. In addition, the substantive contents of the DOE orders as they apply to remediation of radioactively contaminated sites are discussed as TBC guidance.

  7. Spin systems

    CERN Document Server

    Caspers, W J

    1989-01-01

    This book is about spin systems as models for magnetic materials, especially antiferromagnetic lattices. Spin-systems are well-defined models, for which, in special cases, exact properties may be derived. These special cases are for the greater part, one- dimensional and restricted in their applicability, but they may give insight into general properties that also exist in higher dimension. This work pays special attention to qualitative differences between spin lattices of different dimensions. It also replaces the traditional picture of an (ordered) antiferromagnetic state of a Heisenberg sy

  8. Entangled spin chain

    Science.gov (United States)

    Salberger, Olof; Korepin, Vladimir

    We introduce a new model of interacting spin 1/2. It describes interactions of three nearest neighbors. The Hamiltonian can be expressed in terms of Fredkin gates. The Fredkin gate (also known as the controlled swap gate) is a computational circuit suitable for reversible computing. Our construction generalizes the model presented by Peter Shor and Ramis Movassagh to half-integer spins. Our model can be solved by means of Catalan combinatorics in the form of random walks on the upper half plane of a square lattice (Dyck walks). Each Dyck path can be mapped on a wave function of spins. The ground state is an equally weighted superposition of Dyck walks (instead of Motzkin walks). We can also express it as a matrix product state. We further construct a model of interacting spins 3/2 and greater half-integer spins. The models with higher spins require coloring of Dyck walks. We construct a SU(k) symmetric model (where k is the number of colors). The leading term of the entanglement entropy is then proportional to the square root of the length of the lattice (like in the Shor-Movassagh model). The gap closes as a high power of the length of the lattice [5, 11].

  9. Spin dynamics in electron synchrotrons

    International Nuclear Information System (INIS)

    Schmidt, Jan Felix

    2017-01-01

    Providing spin polarized particle beams with circular accelerators requires the consideration of depolarizing resonances which may significantly reduce the desired degree of polarization at specific beam energies. The corresponding spin dynamical effects are typically analyzed with numerical methods. In case of electron beams the influence of the emission of synchrotron radiation has to be taken into account. On short timescales, as in synchrotrons with a fast energy ramp or in damping rings, spin dynamics are investigated with spin tracking algorithms. This thesis presents the spin tracking code Polematrix as a versatile tool to study the impact of synchrotron radiation on spin dynamics. Spin tracking simulations have been performed based on the well established particle tracking code Elegant. The numerical studies demonstrate effects which are responsible for beam depolarization: Synchrotron side bands of depolarizing resonances and decoherence of spin precession. Polematrix can be utilized for any electron accelerator with minimal effort as it imports lattice files from the tracking programs MAD-X or Elegant. Polematrix has been published as open source software. Currently, the Electron Stretcher Accelerator ELSA at Bonn University is the only electron synchrotron worldwide providing a polarized beam. Integer and intrinsic depolarizing resonances are compensated with dedicated countermeasures during the fast energy ramp. Polarization measurements from ELSA demonstrate the particular spin dynamics of electrons and confirm the results of the spin tracking code Polematrix.

  10. Spin electronics

    CERN Document Server

    Buhrman, Robert; Daughton, James; Molnár, Stephan; Roukes, Michael

    2004-01-01

    This report is a comparative review of spin electronics ("spintronics") research and development activities in the United States, Japan, and Western Europe conducted by a panel of leading U.S. experts in the field. It covers materials, fabrication and characterization of magnetic nanostructures, magnetism and spin control in magnetic nanostructures, magneto-optical properties of semiconductors, and magnetoelectronics and devices. The panel's conclusions are based on a literature review and a series of site visits to leading spin electronics research centers in Japan and Western Europe. The panel found that Japan is clearly the world leader in new material synthesis and characterization; it is also a leader in magneto-optical properties of semiconductor devices. Europe is strong in theory pertaining to spin electronics, including injection device structures such as tunneling devices, and band structure predictions of materials properties, and in development of magnetic semiconductors and semiconductor heterost...

  11. Generation of genealogical spin eigenfunctions

    International Nuclear Information System (INIS)

    Grabenstetter, J.E.; Tseng, T.J.; Grein, F.

    1976-01-01

    A method is given for generating the Yamanouchi-Kotani genealogical spin eigenfunctions which requires neither storage of eigenfunctions for smaller numbers of electrons, nor summations of large order, nor explicit use of results from the theory of representations of the symmetric group. An explicit formula is given for the coefficients of expansion in terms of spin products

  12. Spin Conference

    International Nuclear Information System (INIS)

    Anon.

    1983-01-01

    The 5th International Symposium on High Energy Spin Physics met in September at Brookhaven. The symposium has evolved to include a number of diverse specialities: theory, including parity violations and proposed quantum chromodynamics (QCD) tests with polarized beams; experiment, including the large spin effects discovered in high transverse momentum elastic scattering and hyperon production, dibaryons, and magnetic moments; acceleration and storage of polarized protons and electrons; and development of polarized sources and targets

  13. Spin currents in metallic nanostructures

    Energy Technology Data Exchange (ETDEWEB)

    Czeschka, Franz Dominik

    2011-09-05

    A pure spin current, i.e., a flow of angular momentum without accompanying net charge current, is a key ingredient in the field of spintronics. In this thesis, we experimentally investigated two different concepts for pure spin current sources suggested by theory. The first is based on a time-dependent magnetization precession which ''pumps'' a pure spin current into an adjacent non-magnetic conductor. Our experiments quantitatively corroborated important predictions expected theoretically for this approach, including the dependence of the spin current on the sample geometry and the microwave power. Even more important, we could show for the first time that the spin pumping concept is viable in a large variety of ferromagnetic materials and that it only depends on the magnetization damping. Therefore, our experiments established spin pumping as generic phenomenon and demonstrated that it is a powerful way to generate pure spin currents. The second theoretical concept is based on the conversion of charge currents into spin currents in non-magnetic nanostructures via the spin Hall effect. We experimentally investigated this approach in H-shaped, metallic nanodevices, and found that the predictions are linked to requirements not realizable with the present experimental techniques, neither in sample fabrication nor in measurement technique. Indeed, our experimental data could be consistently understood by a spin-independent transport model describing the transition from diffusive to ballistic transport. In addition, the implementation of advanced fabrication and measurement techniques allowed to discover a new non-local phenomenon, the non-local anisotropic magnetoresistance. Finally, we also studied spin-polarized supercurrents carried by spin-triplet Cooper pairs. We found that low resistance interfaces are a key requirement for further experiments in this direction. (orig.)

  14. Exertional Rhabdomyolysis after Spinning.

    Science.gov (United States)

    Jeong, Youjin; Kweon, Hyuk-Jung; Oh, Eun-Jung; Ahn, Ah-Leum; Choi, Jae-Kyung; Cho, Dong-Yung

    2016-11-01

    Any strenuous muscular exercise may trigger rhabdomyolysis. We report an episode of clinically manifested exertional rhabdomyolysis due to stationary cycling, commonly known as spinning. Reports of spinning-related rhabdomyolysis are rare in the English literature, and the current case appears to be the first such case reported in South Korea. A previously healthy 21-year-old Asian woman presented with severe thigh pain and reddish-brown urinary discoloration 24-48 hours after attending a spinning class at a local gymnasium. Paired with key laboratory findings, her symptoms were suggestive of rhabdomyolysis. She required hospital admission to sustain renal function through fluid resuscitation therapy and fluid balance monitoring. Because exertional rhabdomyolysis may occur in any unfit but otherwise healthy individual who indulges in stationary cycling, the potential health risks of this activity must be considered.

  15. Spin modes

    International Nuclear Information System (INIS)

    Gaarde, C.

    1985-01-01

    An analysis of spectra of (p,n) reactions showed that they were very selective in exciting spin modes. Charge exchange reactions at intermediate energies give important new understanding of the M1-type of excitations and of the spin structure of continuum p spectra in general. In this paper, the author discusses three charge exchange reactions: (p,n); ( 3 H,t); and (d,2p) at several targets. Low-lying states and the Δ region are discussed separately. Finally, the charge exchange reaction with heavy ion beams is briefly discussed. (G.J.P./Auth.)

  16. Spinning worlds

    NARCIS (Netherlands)

    Schwarz, H.

    2017-01-01

    The thesis "Spinning Worlds" is about the characterisation of two types of gas-giant exoplanets: Hot Jupiters, with orbital periods of fewer than five days, and young, wide-orbit gas giants, with orbital periods as long as thousands of years. The thesis is based on near-infrared observations of 1

  17. 'ISL pattern reserve requirements for today's spot price,' or 'how many in-place pounds are needed for a mining pattern to be profitable in today's market'

    International Nuclear Information System (INIS)

    Anthony, H.L.

    2000-01-01

    Recent uranium spot market values place additional burdens on the geologist and project manager to identify mineralized ore that will yield a profitable return on investment to the mining venture and its investors. The author reviews the various cost components that comprise the total work effort required to produce uranium via ISL methods to arrive at a suitable ore grade that will guarantee profitably. Amortization of costs based on recent expenditures for typical ISL operations are used in conjunction with wellfield development, operating and restoration costs to determine the ore value required to show a positive return on investment. (author)

  18. Extrinsic spin Hall effect in graphene

    Science.gov (United States)

    Rappoport, Tatiana

    The intrinsic spin-orbit coupling in graphene is extremely weak, making it a promising spin conductor for spintronic devices. In addition, many applications also require the generation of spin currents in graphene. Theoretical predictions and recent experimental results suggest one can engineer the spin Hall effect in graphene by greatly enhancing the spin-orbit coupling in the vicinity of an impurity. The extrinsic spin Hall effect then results from the spin-dependent skew scattering of electrons by impurities in the presence of spin-orbit interaction. This effect can be used to efficiently convert charge currents into spin-polarized currents. I will discuss recent experimental results on spin Hall effect in graphene decorated with adatoms and metallic cluster and show that a large spin Hall effect can appear due to skew scattering. While this spin-orbit coupling is small if compared with what it is found in metals, the effect is strongly enhanced in the presence of resonant scattering, giving rise to robust spin Hall angles. I will present our single impurity scattering calculations done with exact partial-wave expansions and complement the analysis with numerical results from a novel real-space implementation of the Kubo formalism for tight-binding Hamiltonians. The author acknowledges the Brazilian agencies CNPq, CAPES, FAPERJ and INCT de Nanoestruturas de Carbono for financial support.

  19. Spin resonance with trapped ions

    Energy Technology Data Exchange (ETDEWEB)

    Wunderlich, Ch; Balzer, Ch; Hannemann, T; Mintert, F; Neuhauser, W; Reiss, D; Toschek, P E [Institut fuer Laser-Physik, Universitaet Hamburg, Jungiusstrasse 9, 20355 Hamburg (Germany)

    2003-03-14

    A modified ion trap is described where experiments (in particular related to quantum information processing) that usually require optical radiation can be carried out using microwave or radio frequency electromagnetic fields. Instead of applying the usual methods for coherent manipulation of trapped ions, a string of ions in such a modified trap can be treated like a molecule in nuclear magnetic resonance experiments taking advantage of spin-spin coupling. The collection of trapped ions can be viewed as an N-qubit molecule with adjustable spin-spin coupling constants. Given N identically prepared quantum mechanical two-level systems (qubits), the optimal strategy to estimate their quantum state requires collective measurements. Using the ground state hyperfine levels of electrodynamically trapped {sup 171}Yb{sup +}, we have implemented an adaptive algorithm for state estimation involving sequential measurements on arbitrary qubit states.

  20. Spin resonance with trapped ions

    International Nuclear Information System (INIS)

    Wunderlich, Ch; Balzer, Ch; Hannemann, T; Mintert, F; Neuhauser, W; Reiss, D; Toschek, P E

    2003-01-01

    A modified ion trap is described where experiments (in particular related to quantum information processing) that usually require optical radiation can be carried out using microwave or radio frequency electromagnetic fields. Instead of applying the usual methods for coherent manipulation of trapped ions, a string of ions in such a modified trap can be treated like a molecule in nuclear magnetic resonance experiments taking advantage of spin-spin coupling. The collection of trapped ions can be viewed as an N-qubit molecule with adjustable spin-spin coupling constants. Given N identically prepared quantum mechanical two-level systems (qubits), the optimal strategy to estimate their quantum state requires collective measurements. Using the ground state hyperfine levels of electrodynamically trapped 171 Yb + , we have implemented an adaptive algorithm for state estimation involving sequential measurements on arbitrary qubit states

  1. Spin-polarized photoemission

    International Nuclear Information System (INIS)

    Johnson, Peter D.

    1997-01-01

    Spin-polarized photoemission has developed into a versatile tool for the study of surface and thin film magnetism. In this review, we examine the methodology of the technique and its application to a number of different problems, including both valence band and core level studies. After a detailed review of spin-polarization measurement techniques and the related experimental requirements we consider in detail studies of the bulk properties both above and below the Curie temperature. This section also includes a discussion of observations relating to unique metastable phases obtained via epitaxial growth. The application of the technique to the study of surfaces, both clean and adsorbate covered, is reviewed. The report then examines, in detail, studies of the spin-polarized electronic structure of thin films and the related interfacial magnetism. Finally, observations of spin-polarized quantum well states in non-magnetic thin films are discussed with particular reference to their mediation of the oscillatory exchange coupling in related magnetic multilayers. (author)

  2. Spin Coherence in Semiconductor Nanostructures

    National Research Council Canada - National Science Library

    Flatte, Michael E

    2006-01-01

    ... dots, tuning of spin coherence times for electron spin, tuning of dipolar magnetic fields for nuclear spin, spontaneous spin polarization generation and new designs for spin-based teleportation and spin transistors...

  3. Spin-transfer torque generated by a topological insulator

    KAUST Repository

    Mellnik, A. R.

    2014-07-23

    Magnetic devices are a leading contender for the implementation of memory and logic technologies that are non-volatile, that can scale to high density and high speed, and that do not wear out. However, widespread application of magnetic memory and logic devices will require the development of efficient mechanisms for reorienting their magnetization using the least possible current and power. There has been considerable recent progress in this effort; in particular, it has been discovered that spin-orbit interactions in heavy-metal/ferromagnet bilayers can produce strong current-driven torques on the magnetic layer, via the spin Hall effect in the heavy metal or the Rashba-Edelstein effect in the ferromagnet. In the search for materials to provide even more efficient spin-orbit-induced torques, some proposals have suggested topological insulators, which possess a surface state in which the effects of spin-orbit coupling are maximal in the sense that an electron\\' s spin orientation is fixed relative to its propagation direction. Here we report experiments showing that charge current flowing in-plane in a thin film of the topological insulator bismuth selenide (Bi2Se3) at room temperature can indeed exert a strong spin-transfer torque on an adjacent ferromagnetic permalloy (Ni81Fe19) thin film, with a direction consistent with that expected from the topological surface state. We find that the strength of the torque per unit charge current density in Bi 2Se3 is greater than for any source of spin-transfer torque measured so far, even for non-ideal topological insulator films in which the surface states coexist with bulk conduction. Our data suggest that topological insulators could enable very efficient electrical manipulation of magnetic materials at room temperature, for memory and logic applications. © 2014 Macmillan Publishers Limited. All rights reserved.

  4. Massless representations and admissibility condition for higher spin superalgebras

    Energy Technology Data Exchange (ETDEWEB)

    Konstein, S E; Vasiliev, M A

    1989-01-16

    Massless particle representations of various infinite-dimensional higher spin superalgebras proposed previously are constructed. We analyse which of higher spin superalgebras obey the requirement (the admissibility condition) of possessing massless unitary representations with the same spectra of spins as predicted by the structure of gauge fields originating from these superalgebras. It is argued that those higher spin superalgebras, which obey the admissibility condition, can serve as rigid supersymmetries in nontrivial consistent gauge theories of massless fields of all spins.

  5. Electronic structure of spin systems

    Energy Technology Data Exchange (ETDEWEB)

    Saha-Dasgupta, Tanusri

    2016-04-15

    Highlights: • We review the theoretical modeling of quantum spin systems. • We apply the Nth order muffin-tin orbital electronic structure method. • The method shows the importance of chemistry in the modeling. • CuTe{sub 2}O{sub 5} showed a 2-dimensional coupled spin dimer behavior. • Ti substituted Zn{sub 2}VO(PO{sub 4}){sub 2} showed spin gap behavior. - Abstract: Low-dimensional quantum spin systems, characterized by their unconventional magnetic properties, have attracted much attention. Synthesis of materials appropriate to various classes within these systems has made this field very attractive and a site of many activities. The experimental results like susceptibility data are fitted with the theoretical model to derive the underlying spin Hamiltonian. However, often such a fitting procedure which requires correct guess of the assumed spin Hamiltonian leads to ambiguity in deciding the representative model. In this review article, we will describe how electronic structure calculation within the framework of Nth order muffin-tin orbital (NMTO) based Wannier function technique can be utilized to identify the underlying spin model for a large number of such compounds. We will show examples from compounds belonging to vanadates and cuprates.

  6. Digital operation and eye diagrams in spin-lasers

    International Nuclear Information System (INIS)

    Wasner, Evan; Bearden, Sean; Žutić, Igor; Lee, Jeongsu

    2015-01-01

    Digital operation of lasers with injected spin-polarized carriers provides an improved operation over their conventional counterparts with spin-unpolarized carriers. Such spin-lasers can attain much higher bit rates, crucial for optical communication systems. The overall quality of a digital signal in these two types of lasers is compared using eye diagrams and quantified by improved Q-factors and bit-error-rates in spin-lasers. Surprisingly, an optimal performance of spin-lasers requires finite, not infinite, spin-relaxation times, giving a guidance for the design of future spin-lasers

  7. Spin glasses

    International Nuclear Information System (INIS)

    Mookerjee, Abhijit

    1976-01-01

    ''Spin glasses'', are entire class of magnetic alloys of moderate dilution, in which the magnetic atoms are far enough apart to be unlike the pure metal, but close enough so that the indirect exchange energy between them (mediated by the s-d interaction between local moments and conduction electrons) dominates all other energies. Characteristic critical phenomena displayed such as freezing of spin orientation at 'Tsub(c)' and spreading of magnetic ordering, are pointed out. Anomalous behaviour, associated with these critical phenomena, as reflected in : (i) Moessbauer spectroscopy giving hyperfine splitting at Tsub(c), (ii) maxima in susceptibility and remanent magnetism, (iii) thermopower maxima and change in slope, (iv) Characteristic cusp in susceptibility and its removal by very small magnetic fields, and (v) conductivity-resistivity measurements, are discussed. Theoretical developments aimed at explaining these phenomena, in particular, the ideas from percolation and localisation theories, and the approach based on the gellations of polymers, are discussed. Finally, a new approach based on renormalisation group in disordered systems is also briefly mentioned. (K.B.)

  8. Professionalizing the Estonian Reserve Component

    National Research Council Canada - National Science Library

    Everett, William

    1998-01-01

    .... In particular, citizen-soldier reserves can allow nations that do not face immediate external threats, such as Estonia, to meet their security requirements for less money than required by standing forces...

  9. Heat and spin interconversion

    International Nuclear Information System (INIS)

    Ohnuma, Yuichi; Matsuo, Mamoru; Maekawa, Sadamichi; Saitoh, Eeiji

    2017-01-01

    Spin Seebeck and spin Peltier effects, which are mutual conversion phenomena of heat and spin, are discussed on the basis of the microscopic theory. First, the spin Seebeck effect, which is the spin-current generation due to heat current, is discussed. The recent progress in research on the spin Seebeck effect are introduced. We explain the origin of the observed sign changes of the spin Seebeck effect in compensated ferromagnets. Next, the spin Peltier effect, which is the heat-current generation due to spin current, is discussed. Finally, we show that the spin Seebeck and spin Peltier effects are summarized by Onsager's reciprocal relation and derive Kelvin's relation for the spin and heat transports. (author)

  10. Entangled spins and ghost-spins

    Directory of Open Access Journals (Sweden)

    Dileep P. Jatkar

    2017-09-01

    Full Text Available We study patterns of quantum entanglement in systems of spins and ghost-spins regarding them as simple quantum mechanical toy models for theories containing negative norm states. We define a single ghost-spin as in [20] as a 2-state spin variable with an indefinite inner product in the state space. We find that whenever the spin sector is disentangled from the ghost-spin sector (both of which could be entangled within themselves, the reduced density matrix obtained by tracing over all the ghost-spins gives rise to positive entanglement entropy for positive norm states, while negative norm states have an entanglement entropy with a negative real part and a constant imaginary part. However when the spins are entangled with the ghost-spins, there are new entanglement patterns in general. For systems where the number of ghost-spins is even, it is possible to find subsectors of the Hilbert space where positive norm states always lead to positive entanglement entropy after tracing over the ghost-spins. With an odd number of ghost-spins however, we find that there always exist positive norm states with negative real part for entanglement entropy after tracing over the ghost-spins.

  11. Spin transport in nanowires

    OpenAIRE

    Pramanik, S.; bandyopadhyay, S.; Cahay, M.

    2003-01-01

    We study high-field spin transport of electrons in a quasi one-dimensional channel of a $GaAs$ gate controlled spin interferometer (SPINFET) using a semiclassical formalism (spin density matrix evolution coupled with Boltzmann transport equation). Spin dephasing (or depolarization) is predominantly caused by D'yakonov-Perel' relaxation associated with momentum dependent spin orbit coupling effects that arise due to bulk inversion asymmetry (Dresselhaus spin orbit coupling) and structural inve...

  12. Long-range interaction between spins

    International Nuclear Information System (INIS)

    Naik, P.C.; Pradhan, T.

    1981-01-01

    It is shown that invariance of Lagrangian field theory under a class of the coordinate-dependent Lorentz group of transformations requires the introduction of a massless axial vector gauge field which gives rise to a super-weak long-range spin-spin force between particles in vacuum. Recent experiments demonstrating repulsion and attraction between circularly polarised laser beams are interpreted to be due to such a force enhanced by spin polarisation of sodium vapour, through which these beams pass. (author)

  13. Spin voltage generation through optical excitation of complementary spin populations

    Science.gov (United States)

    Bottegoni, Federico; Celebrano, Michele; Bollani, Monica; Biagioni, Paolo; Isella, Giovanni; Ciccacci, Franco; Finazzi, Marco

    2014-08-01

    By exploiting the spin degree of freedom of carriers inside electronic devices, spintronics has a huge potential for quantum computation and dissipationless interconnects. Pure spin currents in spintronic devices should be driven by a spin voltage generator, able to drive the spin distribution out of equilibrium without inducing charge currents. Ideally, such a generator should operate at room temperature, be highly integrable with existing semiconductor technology, and not interfere with other spintronic building blocks that make use of ferromagnetic materials. Here we demonstrate a device that matches these requirements by realizing the spintronic equivalent of a photovoltaic generator. Whereas a photovoltaic generator spatially separates photoexcited electrons and holes, our device exploits circularly polarized light to produce two spatially well-defined electron populations with opposite in-plane spin projections. This is achieved by modulating the phase and amplitude of the light wavefronts entering a semiconductor (germanium) with a patterned metal overlayer (platinum). The resulting light diffraction pattern features a spatially modulated chirality inside the semiconductor, which locally excites spin-polarized electrons thanks to electric dipole selection rules.

  14. Magnetic Nanostructures Spin Dynamics and Spin Transport

    CERN Document Server

    Farle, Michael

    2013-01-01

    Nanomagnetism and spintronics is a rapidly expanding and increasingly important field of research with many applications already on the market and many more to be expected in the near future. This field started in the mid-1980s with the discovery of the GMR effect, recently awarded with the Nobel prize to Albert Fert and Peter Grünberg. The present volume covers the most important and most timely aspects of magnetic heterostructures, including spin torque effects, spin injection, spin transport, spin fluctuations, proximity effects, and electrical control of spin valves. The chapters are written by internationally recognized experts in their respective fields and provide an overview of the latest status.

  15. Lithium reserves and resources

    International Nuclear Information System (INIS)

    Evans, R.K.

    1978-01-01

    As a result of accelerating research efforts in the fields of secondary batteries and thermonuclear power generation, concern has been expressed in certain quarters regarding the availability, in sufficient quantities, of lithium. As part of a recent study by the National Research Council on behalf of the Energy Research and Development Administration, a subpanel was formed to consider the outlook for lithium. Principal areas of concern were reserves, resources and the 'surplus' available for energy applications after allowing for the growth in current lithium applications. Reserves and resources were categorized into four classes ranging from fully proved reserves to resources which are probably dependent upon the marketing of co-products to become economically attractive. Because of the proprietary nature of data on beneficiation and processing recoveries, the tonnages of available lithium are expressed in terms of plant feed. However, highly conservative assumptions have been made concerning mining recoveries and these go a considerable way to accounting for total losses. Western World reserves and resources of all classes are estimated at 10.6 million tonnes Li of which 3.5 million tonnes Li are located in the United States. Current United States capacity, virtually equivalent to Western World capacity, is 4700 tonnes Li and production in 1976 approximated to 3500 tonnes Li. Production for current applications is expected to grow to approx. 10,000 tonnes in year 2000 and 13,000 tonnes a decade later. The massive excess of reserves and resources over that necessary to support conventional requirements has limited the amount of justifiable exploration expenditures; on the last occasion, there was a a major increase in demand (by the USAEA) reserves and capacity were increased rapidly. There are no foreseeable reasons why this shouldn't happen again when the need is clear. (author)

  16. Evaluation of layback spin in figure skating

    Directory of Open Access Journals (Sweden)

    Jastšenjski Ksenija

    2011-01-01

    Full Text Available Layback spin is considered as one of the most beautiful and elegant spins performed in figure skating. It is also one of the required spins in competitive short program in female category. Different techniques of executing layback spin with variations in changing the positions of free parts of the body, as well as the evaluation of layback spin in accordance with ISU rules and regulations, which have been used in all International Skating Federation competitions since 2004 (World and European championships, Olympic Games are presented in this paper. Due to very difficult position of the body while performing a layback spin, it is essential that the skaters who want to master it should have excellent agility (especially of the spinal column and shoulder and knee joints and balance. Layback spin performance requires significant skating knowledge, so it cannot be performed by beginners. Depending on the fl exibility and creativity, a skater can execute various positions of the head, arms, body and free leg while performing a layback spin. In some cases, these variations can increase the level of difficulty, and in others only the mark given for executing this spin.

  17. RHIC spin flipper AC dipole controller

    Energy Technology Data Exchange (ETDEWEB)

    Oddo, P.; Bai, M.; Dawson, C.; Gassner, D.; Harvey, M.; Hayes, T.; Mernick, K.; Minty, M.; Roser, T.; Severino, F.; Smith, K.

    2011-03-28

    The RHIC Spin Flipper's five high-Q AC dipoles which are driven by a swept frequency waveform require precise control of phase and amplitude during the sweep. This control is achieved using FPGA based feedback controllers. Multiple feedback loops are used to and dynamically tune the magnets. The current implementation and results will be presented. Work on a new spin flipper for RHIC (Relativistic Heavy Ion Collider) incorporating multiple dynamically tuned high-Q AC-dipoles has been developed for RHIC spin-physics experiments. A spin flipper is needed to cancel systematic errors by reversing the spin direction of the two colliding beams multiple times during a store. The spin flipper system consists of four DC-dipole magnets (spin rotators) and five AC-dipole magnets. Multiple AC-dipoles are needed to localize the driven coherent betatron oscillation inside the spin flipper. Operationally the AC-dipoles form two swept frequency bumps that minimize the effect of the AC-dipole dipoles outside of the spin flipper. Both AC bumps operate at the same frequency, but are phase shifted from each other. The AC-dipoles therefore require precise control over amplitude and phase making the implementation of the AC-dipole controller the central challenge.

  18. Spin-polarized spin excitation spectroscopy

    International Nuclear Information System (INIS)

    Loth, Sebastian; Lutz, Christopher P; Heinrich, Andreas J

    2010-01-01

    We report on the spin dependence of elastic and inelastic electron tunneling through transition metal atoms. Mn, Fe and Cu atoms were deposited onto a monolayer of Cu 2 N on Cu(100) and individually addressed with the probe tip of a scanning tunneling microscope. Electrons tunneling between the tip and the substrate exchange energy and spin angular momentum with the surface-bound magnetic atoms. The conservation of energy during the tunneling process results in a distinct onset threshold voltage above which the tunneling electrons create spin excitations in the Mn and Fe atoms. Here we show that the additional conservation of spin angular momentum leads to different cross-sections for spin excitations depending on the relative alignment of the surface spin and the spin of the tunneling electron. For this purpose, we developed a technique for measuring the same local spin with a spin-polarized and a non-spin-polarized tip by exchanging the last apex atom of the probe tip between different transition metal atoms. We derive a quantitative model describing the observed excitation cross-sections on the basis of an exchange scattering process.

  19. Unit commitment with probabilistic reserve: An IPSO approach

    International Nuclear Information System (INIS)

    Lee, Tsung-Ying; Chen, Chun-Lung

    2007-01-01

    This paper presents a new algorithm for solution of the nonlinear optimal scheduling problem. This algorithm is named the iteration particle swarm optimization (IPSO). A new index, called iteration best, is incorporated into particle swarm optimization (PSO) to improve the solution quality and computation efficiency. IPSO is applied to solve the unit commitment with probabilistic reserve problem of a power system. The outage cost as well as fuel cost of thermal units was considered in the unit commitment program to evaluate the level of spinning reserve. The optimal scheduling of on line generation units was reached while minimizing the sum of fuel cost and outage cost. A 48 unit power system was used as a numerical example to test the new algorithm. The optimal scheduling of on line generation units could be reached in the testing results while satisfying the requirement of the objective function

  20. Skyrmion creation and annihilation by spin waves

    International Nuclear Information System (INIS)

    Liu, Yizhou; Yin, Gen; Lake, Roger K.; Zang, Jiadong; Shi, Jing

    2015-01-01

    Single skyrmion creation and annihilation by spin waves in a crossbar geometry are theoretically analyzed. A critical spin-wave frequency is required both for the creation and the annihilation of a skyrmion. The minimum frequencies for creation and annihilation are similar, but the optimum frequency for creation is below the critical frequency for skyrmion annihilation. If a skyrmion already exists in the cross bar region, a spin wave below the critical frequency causes the skyrmion to circulate within the central region. A heat assisted creation process reduces the spin-wave frequency and amplitude required for creating a skyrmion. The effective field resulting from the Dzyaloshinskii-Moriya interaction and the emergent field of the skyrmion acting on the spin wave drive the creation and annihilation processes

  1. Adiabatic quantum computing with spin qubits hosted by molecules.

    Science.gov (United States)

    Yamamoto, Satoru; Nakazawa, Shigeaki; Sugisaki, Kenji; Sato, Kazunobu; Toyota, Kazuo; Shiomi, Daisuke; Takui, Takeji

    2015-01-28

    A molecular spin quantum computer (MSQC) requires electron spin qubits, which pulse-based electron spin/magnetic resonance (ESR/MR) techniques can afford to manipulate for implementing quantum gate operations in open shell molecular entities. Importantly, nuclear spins, which are topologically connected, particularly in organic molecular spin systems, are client qubits, while electron spins play a role of bus qubits. Here, we introduce the implementation for an adiabatic quantum algorithm, suggesting the possible utilization of molecular spins with optimized spin structures for MSQCs. We exemplify the utilization of an adiabatic factorization problem of 21, compared with the corresponding nuclear magnetic resonance (NMR) case. Two molecular spins are selected: one is a molecular spin composed of three exchange-coupled electrons as electron-only qubits and the other an electron-bus qubit with two client nuclear spin qubits. Their electronic spin structures are well characterized in terms of the quantum mechanical behaviour in the spin Hamiltonian. The implementation of adiabatic quantum computing/computation (AQC) has, for the first time, been achieved by establishing ESR/MR pulse sequences for effective spin Hamiltonians in a fully controlled manner of spin manipulation. The conquered pulse sequences have been compared with the NMR experiments and shown much faster CPU times corresponding to the interaction strength between the spins. Significant differences are shown in rotational operations and pulse intervals for ESR/MR operations. As a result, we suggest the advantages and possible utilization of the time-evolution based AQC approach for molecular spin quantum computers and molecular spin quantum simulators underlain by sophisticated ESR/MR pulsed spin technology.

  2. Freebie Rhabdomyolysis: A Public Health Concern. Spin Class-Induced Rhabdomyolysis.

    Science.gov (United States)

    Brogan, Maureen; Ledesma, Rudrick; Coffino, Alan; Chander, Praveen

    2017-04-01

    Rhabdomyolysis is a pathologic condition in which intracellular muscle constituents leak into the blood circulation. It is usually caused by muscle trauma. "Spinning" is an indoor form of cycling where participants use a special stationary exercise bicycle with a weighted flywheel and undergo high-intensity cycling classes focusing on endurance. There have been several case reports in the literature of exertional rhabdomyolysis following spin class. Our nephrology practices have diagnosed a number of cases of symptomatic patients presenting to our emergency departments following their first spin classes, with histories and creatinine phosphokinase levels diagnostic of exertional rhabdomyolysis. We present 3 unusual cases of exertional rhabdomyolysis, each occurring after a first spin class. In the first case, rhabdomyolysis developed following 15 minutes of spin class. In the second case, it occurred in a young individual who exercises regularly. In the third case, the patient developed biopsy-proved acute kidney injury secondary to exertional rhabdomyolysis and required hemodialysis. The high-intensity exercise associated with "spin class" comes with significant risks to newcomers. Copyright © 2016 Elsevier Inc. All rights reserved.

  3. Algorithm for the generation of nuclear spin species and nuclear spin statistical weights

    International Nuclear Information System (INIS)

    Balasubramanian, K.

    1982-01-01

    A set of algorithms for the computer generation of nuclear spin species and nuclear spin statistical weights potentially useful in molecular spectroscopy is developed. These algorithms generate the nuclear spin species from group structures known as generalized character cycle indices (GCCIs). Thus the required input for these algorithms is just the set of all GCCIs for the symmetry group of the molecule which can be computed easily from the character table. The algorithms are executed and illustrated with examples

  4. Circuit quantum electrodynamics with a spin qubit.

    Science.gov (United States)

    Petersson, K D; McFaul, L W; Schroer, M D; Jung, M; Taylor, J M; Houck, A A; Petta, J R

    2012-10-18

    Electron spins trapped in quantum dots have been proposed as basic building blocks of a future quantum processor. Although fast, 180-picosecond, two-quantum-bit (two-qubit) operations can be realized using nearest-neighbour exchange coupling, a scalable, spin-based quantum computing architecture will almost certainly require long-range qubit interactions. Circuit quantum electrodynamics (cQED) allows spatially separated superconducting qubits to interact via a superconducting microwave cavity that acts as a 'quantum bus', making possible two-qubit entanglement and the implementation of simple quantum algorithms. Here we combine the cQED architecture with spin qubits by coupling an indium arsenide nanowire double quantum dot to a superconducting cavity. The architecture allows us to achieve a charge-cavity coupling rate of about 30 megahertz, consistent with coupling rates obtained in gallium arsenide quantum dots. Furthermore, the strong spin-orbit interaction of indium arsenide allows us to drive spin rotations electrically with a local gate electrode, and the charge-cavity interaction provides a measurement of the resulting spin dynamics. Our results demonstrate how the cQED architecture can be used as a sensitive probe of single-spin physics and that a spin-cavity coupling rate of about one megahertz is feasible, presenting the possibility of long-range spin coupling via superconducting microwave cavities.

  5. Flying spin qualities testing of airplane

    Directory of Open Access Journals (Sweden)

    Kostić Čedomir J.

    2015-01-01

    Full Text Available In this paper is presented the theoretical analysis of origins and characteristics of spinning motion. There are precise explanation of every stage spin flight and basic meaning of notion. Personated equation of motion in spin and equitation of motion airplane in settled spin motion, analysis of them and general recommendation for pilots for recovering from spins. Introduced in valid military and civil specifications flight test demonstration requirements for departure resistance and flying stall and spin qualities testing of airplane. Special attention was given on predicting departure, stall and spin susceptibility and theoretical analysis in the name of magnify flight testing security. There are explanation of test equipment and methodology of flying qualities testing of airplanes. Like a support of this theme are described method and results of flight stall and spin qualities testing of airplane G-4(N-62 super see-gull with precise recommendation for pilots for recovering from spins, from TOC SLI VS (Technical testing center, department for fight testing Air Force of Serbia.

  6. Spin-Mechatronics

    Science.gov (United States)

    Matsuo, Mamoru; Saitoh, Eiji; Maekawa, Sadamichi

    2017-01-01

    We investigate the interconversion phenomena between spin and mechanical angular momentum in moving objects. In particular, the recent results on spin manipulation and spin-current generation by mechanical motion are examined. In accelerating systems, spin-dependent gauge fields emerge, which enable the conversion from mechanical angular momentum into spins. Such a spin-mechanical effect is predicted by quantum theory in a non-inertial frame. Experiments which confirm the effect, i.e., the resonance frequency shift in nuclear magnetic resonance, the stray field measurement of rotating metals, and electric voltage generation in liquid metals, are discussed.

  7. Heavy spin-2 Dark Matter

    Energy Technology Data Exchange (ETDEWEB)

    Babichev, Eugeny [Laboratoire de Physique Théorique, CNRS, Univ. Paris-Sud, Université Paris-Saclay,91405 Orsay (France); UPMC-CNRS, UMR7095, Institut d’Astrophysique de Paris, GReCO,98bis boulevard Arago, F-75014 Paris (France); Marzola, Luca; Raidal, Martti [National Institute of Chemical Physics and Biophysics,Rävala 10, 10143 Tallinn (Estonia); Laboratory of Theoretical Physics, Institute of Physics, University of Tartu,Ravila 14c, 50411 Tartu (Estonia); Schmidt-May, Angnis [Institut für Theoretische Physik, Eidgenössische Technische Hochschule Zürich,Wolfgang-Pauli-Strasse 27, 8093 Zürich (Switzerland); Urban, Federico; Veermäe, Hardi [National Institute of Chemical Physics and Biophysics,Rävala 10, 10143 Tallinn (Estonia); Strauss, Mikael von [UPMC-CNRS, UMR7095, Institut d’Astrophysique de Paris, GReCO,98bis boulevard Arago, F-75014 Paris (France)

    2016-09-12

    We provide further details on a recent proposal addressing the nature of the dark sectors in cosmology and demonstrate that all current observations related to Dark Matter can be explained by the presence of a heavy spin-2 particle. Massive spin-2 fields and their gravitational interactions are uniquely described by ghost-free bimetric theory, which is a minimal and natural extension of General Relativity. In this setup, the largeness of the physical Planck mass is naturally related to extremely weak couplings of the heavy spin-2 field to baryonic matter and therefore explains the absence of signals in experiments dedicated to Dark Matter searches. It also ensures the phenomenological viability of our model as we confirm by comparing it with cosmological and local tests of gravity. At the same time, the spin-2 field possesses standard gravitational interactions and it decays universally into all Standard Model fields but not into massless gravitons. Matching the measured DM abundance together with the requirement of stability constrains the spin-2 mass to be in the 1 to 100 TeV range.

  8. Induction-detection electron spin resonance with spin sensitivity of a few tens of spins

    Energy Technology Data Exchange (ETDEWEB)

    Artzi, Yaron; Twig, Ygal; Blank, Aharon [Schulich Faculty of Chemistry Technion—Israel Institute of Technology, Haifa 32000 (Israel)

    2015-02-23

    Electron spin resonance (ESR) is a spectroscopic method that addresses electrons in paramagnetic materials directly through their spin properties. ESR has many applications, ranging from semiconductor characterization to structural biology and even quantum computing. Although it is very powerful and informative, ESR traditionally suffers from low sensitivity, requiring many millions of spins to get a measureable signal with commercial systems using the Faraday induction-detection principle. In view of this disadvantage, significant efforts were made recently to develop alternative detection schemes based, for example, on force, optical, or electrical detection of spins, all of which can reach single electron spin sensitivity. This sensitivity, however, comes at the price of limited applicability and usefulness with regard to real scientific and technological issues facing modern ESR which are currently dealt with conventional induction-detection ESR on a daily basis. Here, we present the most sensitive experimental induction-detection ESR setup and results ever recorded that can detect the signal from just a few tens of spins. They were achieved thanks to the development of an ultra-miniature micrometer-sized microwave resonator that was operated at ∼34 GHz at cryogenic temperatures in conjunction with a unique cryogenically cooled low noise amplifier. The test sample used was isotopically enriched phosphorus-doped silicon, which is of significant relevance to spin-based quantum computing. The sensitivity was experimentally verified with the aid of a unique high-resolution ESR imaging approach. These results represent a paradigm shift with respect to the capabilities and possible applications of induction-detection-based ESR spectroscopy and imaging.

  9. Spin in hadron physics

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2006-07-01

    The following topics were ealt with: Hadron physics with proton and deuteron probes, physics projects with Georgian participation, spin physics with antiprotons and leptons, spin filtering experiments, ISTC projects, technical issues for FAIR. (HSI)

  10. Dynamic nuclear spin polarization

    Energy Technology Data Exchange (ETDEWEB)

    Stuhrmann, H B [GKSS-Forschungszentrum Geesthacht GmbH (Germany)

    1996-11-01

    Polarized neutron scattering from dynamic polarized targets has been applied to various hydrogenous materials at different laboratories. In situ structures of macromolecular components have been determined by nuclear spin contrast variation with an unprecedented precision. The experiments of selective nuclear spin depolarisation not only opened a new dimension to structural studies but also revealed phenomena related to propagation of nuclear spin polarization and the interplay of nuclear polarisation with the electronic spin system. The observation of electron spin label dependent nuclear spin polarisation domains by NMR and polarized neutron scattering opens a way to generalize the method of nuclear spin contrast variation and most importantly it avoids precontrasting by specific deuteration. It also likely might tell us more about the mechanism of dynamic nuclear spin polarisation. (author) 4 figs., refs.

  11. Vector spin modeling for magnetic tunnel junctions with voltage dependent effects

    International Nuclear Information System (INIS)

    Manipatruni, Sasikanth; Nikonov, Dmitri E.; Young, Ian A.

    2014-01-01

    Integration and co-design of CMOS and spin transfer devices requires accurate vector spin conduction modeling of magnetic tunnel junction (MTJ) devices. A physically realistic model of the MTJ should comprehend the spin torque dynamics of nanomagnet interacting with an injected vector spin current and the voltage dependent spin torque. Vector spin modeling allows for calculation of 3 component spin currents and potentials along with the charge currents/potentials in non-collinear magnetic systems. Here, we show 4-component vector spin conduction modeling of magnetic tunnel junction devices coupled with spin transfer torque in the nanomagnet. Nanomagnet dynamics, voltage dependent spin transport, and thermal noise are comprehended in a self-consistent fashion. We show comparison of the model with experimental magnetoresistance (MR) of MTJs and voltage degradation of MR with voltage. Proposed model enables MTJ circuit design that comprehends voltage dependent spin torque effects, switching error rates, spin degradation, and back hopping effects

  12. A Beautiful Spin

    International Nuclear Information System (INIS)

    Ji Xiangdong

    2003-01-01

    Spin is a beautiful concept that plays an ever important role in modern physics. In this talk, I start with a discussion of the origin of spin, and then turn to three themes in which spin has been crucial in subatomic physics: a lab to explore physics beyond the standard model, a tool to measure physical observables that are hard to obtain otherwise, a probe to unravel nonperturbative QCD. I conclude with some remarks on a world without spin

  13. Spin at Lausanne

    International Nuclear Information System (INIS)

    Anon.

    1980-01-01

    From 25 September to 1 October, some 150 spin enthusiasts gathered in Lausanne for the 1980 International Symposium on High Energy Physics with Polarized Beams and Polarized Targets. The programme was densely packed, covering physics interests with spin as well as the accelerator and target techniques which make spin physics possible

  14. Spin-Caloritronic Batteries

    DEFF Research Database (Denmark)

    Yu, Xiao-Qin; Zhu, Zhen-Gang; Su, Gang

    2017-01-01

    The thermoelectric performance of a topological energy converter is analyzed. The H-shaped device is based on a combination of transverse topological effects involving the spin: the inverse spin Hall effect and the spin Nernst effect. The device can convert a temperature drop in one arm into an e...

  15. Spinning Eggs and Ballerinas

    Science.gov (United States)

    Cross, Rod

    2013-01-01

    Measurements are presented on the rise of a spinning egg. It was found that the spin, the angular momentum and the kinetic energy all decrease as the egg rises, unlike the case of a ballerina who can increase her spin and kinetic energy by reducing her moment of inertia. The observed effects can be explained, in part, in terms of rolling friction…

  16. Parallel computer calculation of quantum spin lattices

    International Nuclear Information System (INIS)

    Lamarcq, J.

    1998-01-01

    Numerical simulation allows the theorists to convince themselves about the validity of the models they use. Particularly by simulating the spin lattices one can judge about the validity of a conjecture. Simulating a system defined by a large number of degrees of freedom requires highly sophisticated machines. This study deals with modelling the magnetic interactions between the ions of a crystal. Many exact results have been found for spin 1/2 systems but not for systems of other spins for which many simulation have been carried out. The interest for simulations has been renewed by the Haldane's conjecture stipulating the existence of a energy gap between the ground state and the first excited states of a spin 1 lattice. The existence of this gap has been experimentally demonstrated. This report contains the following four chapters: 1. Spin systems; 2. Calculation of eigenvalues; 3. Programming; 4. Parallel calculation

  17. Spin physics in semiconductors

    CERN Document Server

    2017-01-01

    This book offers an extensive introduction to the extremely rich and intriguing field of spin-related phenomena in semiconductors. In this second edition, all chapters have been updated to include the latest experimental and theoretical research. Furthermore, it covers the entire field: bulk semiconductors, two-dimensional semiconductor structures, quantum dots, optical and electric effects, spin-related effects, electron-nuclei spin interactions, Spin Hall effect, spin torques, etc. Thanks to its self-contained style, the book is ideally suited for graduate students and researchers new to the field.

  18. Inverse spin Hall effect by spin injection

    Science.gov (United States)

    Liu, S. Y.; Horing, Norman J. M.; Lei, X. L.

    2007-09-01

    Motivated by a recent experiment [S. O. Valenzuela and M. Tinkham, Nature (London) 442, 176 (2006)], the authors present a quantitative microscopic theory to investigate the inverse spin-Hall effect with spin injection into aluminum considering both intrinsic and extrinsic spin-orbit couplings using the orthogonalized-plane-wave method. Their theoretical results are in good agreement with the experimental data. It is also clear that the magnitude of the anomalous Hall resistivity is mainly due to contributions from extrinsic skew scattering.

  19. Bulk electron spin polarization generated by the spin Hall current

    OpenAIRE

    Korenev, V. L.

    2005-01-01

    It is shown that the spin Hall current generates a non-equilibrium spin polarization in the interior of crystals with reduced symmetry in a way that is drastically different from the previously well-known equilibrium polarization during the spin relaxation process. The steady state spin polarization value does not depend on the strength of spin-orbit interaction offering possibility to generate relatively high spin polarization even in the case of weak spin-orbit coupling.

  20. Bulk electron spin polarization generated by the spin Hall current

    Science.gov (United States)

    Korenev, V. L.

    2006-07-01

    It is shown that the spin Hall current generates a nonequilibrium spin polarization in the interior of crystals with reduced symmetry in a way that is drastically different from the previously well-known “equilibrium” polarization during the spin relaxation process. The steady state spin polarization value does not depend on the strength of spin-orbit interaction offering possibility to generate relatively high spin polarization even in the case of weak spin-orbit coupling.

  1. Muon spin relaxation in random spin systems

    International Nuclear Information System (INIS)

    Toshimitsu Yamazaki

    1981-01-01

    The longitudinal relaxation function Gsub(z)(t) of the positive muon can reflect dynamical characters of local field in a unique way even when the correlation time is longer than the Larmor period of local field. This method has been applied to studies of spin dynamics in spin glass systems, revealing sharp but continuous temperature dependence of the correlation time. Its principle and applications are reviewed. (author)

  2. Spin-forming Project Report

    Energy Technology Data Exchange (ETDEWEB)

    Switzner, Nathan; Henry, Dick

    2009-03-20

    In a second development order, spin-forming equipment was again evaluated using the test shape, a hemispherical shell. In this second development order, pure vanadium and alloy titanium (Ti-6Al-4V) were spin-formed, as well as additional copper and 21-6-9 stainless. In the first development order the following materials had been spin-formed: copper (alloy C11000 ETP), 6061 aluminum, 304L stainless steel, 21-6-9 stainless steel, and tantalum-2.5% tungsten. Significant challenges included properly adjusting the rotations-per-minute (RPM), cracking at un-beveled edges and laser marks, redressing of notches, surface cracking, non-uniform temperature evolution in the titanium, and cracking of the tailstock. Lessons learned were that 300 RPM worked better than 600 RPM for most materials (at the feed rate of 800 mm/min); beveling the edges to lower the stress reduces edge cracking; notches, laser marks, or edge defects in the preform doom the process to cracking and failure; coolant is required for vanadium spin-forming; increasing the number of passes to nine or more eliminates surface cracking for vanadium; titanium develops a hot zone in front of the rollers; and the tailstock should be redesigned to eliminate the cylindrical stress concentrator in the center.

  3. A molecular spin-photovoltaic device.

    Science.gov (United States)

    Sun, Xiangnan; Vélez, Saül; Atxabal, Ainhoa; Bedoya-Pinto, Amilcar; Parui, Subir; Zhu, Xiangwei; Llopis, Roger; Casanova, Fèlix; Hueso, Luis E

    2017-08-18

    We fabricated a C 60 fullerene-based molecular spin-photovoltaic device that integrates a photovoltaic response with the spin transport across the molecular layer. The photovoltaic response can be modified under the application of a small magnetic field, with a magnetophotovoltage of up to 5% at room temperature. Device functionalities include a magnetic current inverter and the presence of diverging magnetocurrent at certain illumination levels that could be useful for sensing. Completely spin-polarized currents can be created by balancing the external partially spin-polarized injection with the photogenerated carriers. Copyright © 2017 The Authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. No claim to original U.S. Government Works.

  4. Spin entanglement, decoherence and Bohm's EPR paradox

    OpenAIRE

    Cavalcanti, E. G.; Drummond, P. D.; Bachor, H. A.; Reid, M. D.

    2007-01-01

    We obtain criteria for entanglement and the EPR paradox for spin-entangled particles and analyse the effects of decoherence caused by absorption and state purity errors. For a two qubit photonic state, entanglement can occur for all transmission efficiencies. In this case, the state preparation purity must be above a threshold value. However, Bohm's spin EPR paradox can be achieved only above a critical level of loss. We calculate a required efficiency of 58%, which appears achievable with cu...

  5. Spin injection and transport in semiconductor and metal nanostructures

    Science.gov (United States)

    Zhu, Lei

    In this thesis we investigate spin injection and transport in semiconductor and metal nanostructures. To overcome the limitation imposed by the low efficiency of spin injection and extraction and strict requirements for retention of spin polarization within the semiconductor, novel device structures with additional logic functionality and optimized device performance have been developed. Weak localization/antilocalization measurements and analysis are used to assess the influence of surface treatments on elastic, inelastic and spin-orbit scatterings during the electron transport within the two-dimensional electron layer at the InAs surface. Furthermore, we have used spin-valve and scanned probe microscopy measurements to investigate the influence of sulfur-based surface treatments and electrically insulating barrier layers on spin injection into, and spin transport within, the two-dimensional electron layer at the surface of p-type InAs. We also demonstrate and analyze a three-terminal, all-electrical spintronic switching device, combining charge current cancellation by appropriate device biasing and ballistic electron transport. The device yields a robust, electrically amplified spin-dependent current signal despite modest efficiency in electrical injection of spin-polarized electrons. Detailed analyses provide insight into the advantages of ballistic, as opposed to diffusive, transport in device operation, as well as scalability to smaller dimensions, and allow us to eliminate the possibility of phenomena unrelated to spin transport contributing to the observed device functionality. The influence of the device geometry on magnetoresistance of nanoscale spin-valve structures is also demonstrated and discussed. Shortcomings of the simplified one-dimensional spin diffusion model for spin valve are elucidated, with comparison of the thickness and the spin diffusion length in the nonmagnetic channel as the criterion for validity of the 1D model. Our work contributes

  6. Securities issues in reserves reporting

    International Nuclear Information System (INIS)

    Legg, M.B.

    1997-01-01

    Securities issues in oil and gas reserves reporting were discussed. Alberta requires specific information regarding important oil and gas properties, plants, facilities and installations. When preparing the reserves report, the following elements are important to consider: (1) the author of the report must be a registered professional engineer or registered professional geologist, (2) the report itself must be an engineering document, (3) the content of the report must be extensive, (4) it should be prepared in accordance with petroleum engineering and evaluation practices, and must include a summary of estimated net reserves

  7. Spin Hall effects

    Science.gov (United States)

    Sinova, Jairo; Valenzuela, Sergio O.; Wunderlich, J.; Back, C. H.; Jungwirth, T.

    2015-10-01

    Spin Hall effects are a collection of relativistic spin-orbit coupling phenomena in which electrical currents can generate transverse spin currents and vice versa. Despite being observed only a decade ago, these effects are already ubiquitous within spintronics, as standard spin-current generators and detectors. Here the theoretical and experimental results that have established this subfield of spintronics are reviewed. The focus is on the results that have converged to give us the current understanding of the phenomena, which has evolved from a qualitative to a more quantitative measurement of spin currents and their associated spin accumulation. Within the experimental framework, optical-, transport-, and magnetization-dynamics-based measurements are reviewed and linked to both phenomenological and microscopic theories of the effect. Within the theoretical framework, the basic mechanisms in both the extrinsic and intrinsic regimes are reviewed, which are linked to the mechanisms present in their closely related phenomenon in ferromagnets, the anomalous Hall effect. Also reviewed is the connection to the phenomenological treatment based on spin-diffusion equations applicable to certain regimes, as well as the spin-pumping theory of spin generation used in many measurements of the spin Hall angle. A further connection to the spin-current-generating spin Hall effect to the inverse spin galvanic effect is given, in which an electrical current induces a nonequilibrium spin polarization. This effect often accompanies the spin Hall effect since they share common microscopic origins. Both can exhibit the same symmetries when present in structures comprising ferromagnetic and nonmagnetic layers through their induced current-driven spin torques or induced voltages. Although a short chronological overview of the evolution of the spin Hall effect field and the resolution of some early controversies is given, the main body of this review is structured from a pedagogical

  8. The susceptibilities in the spin-S Ising model

    International Nuclear Information System (INIS)

    Ainane, A.; Saber, M.

    1995-08-01

    The susceptibilities of the spin-S Ising model are evaluated using the effective field theory introduced by Tucker et al. for studying general spin-S Ising model. The susceptibilities are studied for all spin values from S = 1/2 to S = 5/2. (author). 12 refs, 4 figs

  9. Neutron spin quantum precession using multilayer spin splitters and a phase-spin echo interferometer

    International Nuclear Information System (INIS)

    Ebisawa, Toru; Tasaki, Seiji; Kawai, Takeshi; Hino, Masahiro; Akiyoshi, Tsunekazu; Achiwa, Norio; Otake, Yoshie; Funahashi, Haruhiko.

    1996-01-01

    Neutron spin quantum precession by multilayer spin splitter has been demonstrated using a new spin interferometer. The multilayer spin splitter consists of a magnetic multilayer mirror on top, followed by a gap layer and a non magnetic multilayer mirror which are evaporated on a silicon substrate. Using the multilayer spin splitter, a polarized neutron wave in a magnetic field perpendicular to the polarization is split into two spin eigenstates with a phase shift in the direction of the magnetic field. The spin quantum precession is equal to the phase shift, which depends on the effective thickness of the gap layer. The demonstration experiments verify the multilayer spin splitter as a neutron spin precession device as well as the coherent superposition principle of the two spin eigenstates. We have developed a new phase-spin echo interferometer using the multilayer spin splitters. We present successful performance tests of the multilayer spin splitter and the phase-spin echo interferometer. (author)

  10. Robust Co-Optimization to Energy and Reserve Joint Dispatch Considering Wind Power Generation and Zonal Reserve Constraints in Real-Time Electricity Markets

    Directory of Open Access Journals (Sweden)

    Chunlai Li

    2017-07-01

    Full Text Available This paper proposes an energy and reserve joint dispatch model based on a robust optimization approach in real-time electricity markets, considering wind power generation uncertainties as well as zonal reserve constraints under both normal and N-1 contingency conditions. In the proposed model, the operating reserves are classified as regulating reserve and spinning reserve according to the response performance. More specifically, the regulating reserve is usually utilized to reduce the gap due to forecasting errors, while the spinning reserve is commonly adopted to enhance the ability for N-1 contingencies. Since the transmission bottlenecks may inhibit the deliverability of reserve, the zonal placement of spinning reserve is considered in this paper to improve the reserve deliverability under the contingencies. Numerical results on the IEEE 118-bus test system show the effectiveness of the proposed model.

  11. Higher spin gauge theories

    CERN Document Server

    Henneaux, Marc; Vasiliev, Mikhail A

    2017-01-01

    Symmetries play a fundamental role in physics. Non-Abelian gauge symmetries are the symmetries behind theories for massless spin-1 particles, while the reparametrization symmetry is behind Einstein's gravity theory for massless spin-2 particles. In supersymmetric theories these particles can be connected also to massless fermionic particles. Does Nature stop at spin-2 or can there also be massless higher spin theories. In the past strong indications have been given that such theories do not exist. However, in recent times ways to evade those constraints have been found and higher spin gauge theories have been constructed. With the advent of the AdS/CFT duality correspondence even stronger indications have been given that higher spin gauge theories play an important role in fundamental physics. All these issues were discussed at an international workshop in Singapore in November 2015 where the leading scientists in the field participated. This volume presents an up-to-date, detailed overview of the theories i...

  12. The Nuclear Spin Nanomagnet

    OpenAIRE

    Korenev, V. L.

    2007-01-01

    Linearly polarized light tuned slightly below the optical transition of the negatively charged exciton (trion) in a single quantum dot causes the spontaneous nuclear spin polarization (self-polarization) at a level close to 100%. The effective magnetic field of spin-polarized nuclei brings the optical transition energy into resonance with photon energy. The resonantly enhanced Overhauser effect sustains the stability of the nuclear self-polarization even in the absence of spin polarization of...

  13. Max Auwaerter symposium: spin mapping and spin manipulation on the atomic scale

    International Nuclear Information System (INIS)

    Wiesendanger, R.

    2008-01-01

    Full text: A fundamental understanding of magnetic and spin-dependent phenomena requires the determination of spin structures and spin excitations down to the atomic scale. The direct visualization of atomic-scale spin structures has first been accomplished for magnetic metals by combining the atomic resolution capability of Scanning Tunnelling Microscopy (STM) with spin sensitivity, based on vacuum tunnelling of spin-polarized electrons. The resulting technique, Spin-Polarized Scanning Tunnelling Microscopy (SP-STM), nowadays provides unprecedented insight into collinear and non-collinear spin structures at surfaces of magnetic nanostructures and has already led to the discovery of new types of magnetic order at the nanoscale. More recently, the development of subkelvin SP-STM has allowed studies of ground-state magnetic properties of individual magnetic adatoms on non-magnetic substrates as well as the magnetic interactions between them. Based on SP-STM experiments performed at temperatures of 300 mK, indirect magnetic exchange interactions at the sub-milli-electronvolt energy scale between individual paramagnetic adatoms as well as between adatoms and nearby magnetic nanostructures could directly be revealed in real space up to distances of several nanometers. In both cases we have observed an oscillatory behavior of the magnetic exchange coupling, alternating between ferromagnetic and antiferromagnetic, as a function of distance. Moreover, the detection of spin-dependent exchange and correlation forces has allowed a first direct real-space observation of spin structures at surfaces of antiferromagnetic insulators. This new type of scanning probe microscopy, called Magnetic Exchange Force Microscopy (MExFM), offers a powerful new tool to investigate different types of spin-spin interactions based on direct-, super-, or RKKY-type exchange down to the atomic level. By combining MExFM with high-precision measurements of damping forces, localized or confined spin

  14. A controllable spin prism

    International Nuclear Information System (INIS)

    Hakioglu, T

    2009-01-01

    Based on Khodas et al (2004 Phys. Rev. Lett. 92 086602), we propose a device acting like a controllable prism for an incident spin. The device is a large quantum well where Rashba and Dresselhaus spin-orbit interactions are present and controlled by the plunger gate potential, the electric field and the barrier height. A totally destructive interference can be manipulated externally between the Rashba and Dresselhaus couplings. The spin-dependent transmission/reflection amplitudes are calculated as the control parameters are changed. The device operates as a spin prism/converter/filter in different regimes and may stimulate research in promising directions in spintronics in analogy with linear optics.

  15. Operator spin foam models

    International Nuclear Information System (INIS)

    Bahr, Benjamin; Hellmann, Frank; Kaminski, Wojciech; Kisielowski, Marcin; Lewandowski, Jerzy

    2011-01-01

    The goal of this paper is to introduce a systematic approach to spin foams. We define operator spin foams, that is foams labelled by group representations and operators, as our main tool. A set of moves we define in the set of the operator spin foams (among other operations) allows us to split the faces and the edges of the foams. We assign to each operator spin foam a contracted operator, by using the contractions at the vertices and suitably adjusted face amplitudes. The emergence of the face amplitudes is the consequence of assuming the invariance of the contracted operator with respect to the moves. Next, we define spin foam models and consider the class of models assumed to be symmetric with respect to the moves we have introduced, and assuming their partition functions (state sums) are defined by the contracted operators. Briefly speaking, those operator spin foam models are invariant with respect to the cellular decomposition, and are sensitive only to the topology and colouring of the foam. Imposing an extra symmetry leads to a family we call natural operator spin foam models. This symmetry, combined with assumed invariance with respect to the edge splitting move, determines a complete characterization of a general natural model. It can be obtained by applying arbitrary (quantum) constraints on an arbitrary BF spin foam model. In particular, imposing suitable constraints on a spin(4) BF spin foam model is exactly the way we tend to view 4D quantum gravity, starting with the BC model and continuing with the Engle-Pereira-Rovelli-Livine (EPRL) or Freidel-Krasnov (FK) models. That makes our framework directly applicable to those models. Specifically, our operator spin foam framework can be translated into the language of spin foams and partition functions. Among our natural spin foam models there are the BF spin foam model, the BC model, and a model corresponding to the EPRL intertwiners. Our operator spin foam framework can also be used for more general spin

  16. PREFACE: Spin Electronics

    Science.gov (United States)

    Dieny, B.; Sousa, R.; Prejbeanu, L.

    2007-04-01

    Conventional electronics has in the past ignored the spin on the electron, however things began to change in 1988 with the discovery of giant magnetoresistance in metallic thin film stacks which led to the development of a new research area, so called spin-electronics. In the last 10 years, spin-electronics has achieved a number of breakthroughs from the point of view of both basic science and application. Materials research has led to several major discoveries: very large tunnel magnetoresistance effects in tunnel junctions with crystalline barriers due to a new spin-filtering mechanism associated with the spin-dependent symmetry of the electron wave functions new magnetic tunnelling barriers leading to spin-dependent tunnelling barrier heights and acting as spin-filters magnetic semiconductors with increasingly high ordering temperature. New phenomena have been predicted and observed: the possibility of acting on the magnetization of a magnetic nanostructure with a spin-polarized current. This effect, due to a transfer of angular momentum between the spin polarized conduction electrons and the local magnetization, can be viewed as the reciprocal of giant or tunnel magnetoresistance. It can be used to switch the magnetization of a magnetic nanostructure or to generate steady magnetic excitations in the system. the possibility of generating and manipulating spin current without charge current by creating non-equilibrium local accumulation of spin up or spin down electrons. The range of applications of spin electronics materials and phenomena is expanding: the first devices based on giant magnetoresistance were the magnetoresistive read-heads for computer disk drives. These heads, introduced in 1998 with current-in plane spin-valves, have evolved towards low resistance tunnel magnetoresistice heads in 2005. Besides magnetic recording technology, these very sensitive magnetoresistive sensors are finding applications in other areas, in particular in biology. magnetic

  17. Kinetic models in spin chemistry. 1. The hyperfine interaction

    DEFF Research Database (Denmark)

    Mojaza, M.; Pedersen, J. B.

    2012-01-01

    Kinetic models for quantum systems are quite popular due to their simplicity, although they are difficult to justify. We show that the transformation from quantum to kinetic description can be done exactly for the hyperfine interaction of one nuclei with arbitrary spin; more spins are described w...... induced enhancement of the reaction yield. (C) 2012 Elsevier B.V. All rights reserved....

  18. Topologically Massive Higher Spin Gravity

    NARCIS (Netherlands)

    Bagchi, A.; Lal, S.; Saha, A.; Sahoo, B.

    2011-01-01

    We look at the generalisation of topologically massive gravity (TMG) to higher spins, specifically spin-3. We find a special "chiral" point for the spin-three, analogous to the spin-two example, which actually coincides with the usual spin-two chiral point. But in contrast to usual TMG, there is the

  19. Spin-orbit and spin-lattice coupling

    International Nuclear Information System (INIS)

    Bauer, Gerrit E.W.; Ziman, Timothy; Mori, Michiyasu

    2014-01-01

    We pursued theoretical research on the coupling of electron spins in the condensed matter to the lattice as mediated by the spin-orbit interaction with special focus on the spin and anomalous Hall effects. (author)

  20. 47 CFR 80.146 - [Reserved

    Science.gov (United States)

    2010-10-01

    ... MARITIME SERVICES Operating Requirements and Procedures Shipboard General Purpose Watches § 80.146 [Reserved] ... 47 Telecommunication 5 2010-10-01 2010-10-01 false [Reserved] 80.146 Section 80.146...

  1. 47 CFR 80.145 - [Reserved

    Science.gov (United States)

    2010-10-01

    ... MARITIME SERVICES Operating Requirements and Procedures Special Procedures-Ship Stations § 80.145 [Reserved] Shipboard General Purpose Watches ... 47 Telecommunication 5 2010-10-01 2010-10-01 false [Reserved] 80.145 Section 80.145...

  2. Current-based detection of nonlocal spin transport in graphene for spin-based logic applications

    Science.gov (United States)

    Wen, Hua; Zhu, Tiancong; Luo, Yunqiu Kelly; Amamou, Walid; Kawakami, Roland K.

    2014-05-01

    Graphene has been proposed for novel spintronic devices due to its robust and efficient spin transport properties at room temperature. Some of the most promising proposals require current-based readout for integration purposes, but the current-based detection of spin accumulation has not yet been developed. In this work, we demonstrate current-based detection of spin transport in graphene using a modified nonlocal geometry. By adding a variable shunt resistor in parallel to the nonlocal voltmeter, we are able to systematically cross over from the conventional voltage-based detection to current-based detection. As the shunt resistor is reduced, the output current from the spin accumulation increases as the shunt resistance drops below a characteristic value R*. We analyze this behavior using a one-dimensional drift-diffusion model, which accounts well for the observed behavior. These results provide the experimental and theoretical foundation for current-based detection of nonlocal spin transport.

  3. Parallel computer calculation of quantum spin lattices; Calcul de chaines de spins quantiques sur ordinateur parallele

    Energy Technology Data Exchange (ETDEWEB)

    Lamarcq, J. [Service de Physique Theorique, CEA Centre d`Etudes de Saclay, 91 - Gif-sur-Yvette (France)

    1998-07-10

    Numerical simulation allows the theorists to convince themselves about the validity of the models they use. Particularly by simulating the spin lattices one can judge about the validity of a conjecture. Simulating a system defined by a large number of degrees of freedom requires highly sophisticated machines. This study deals with modelling the magnetic interactions between the ions of a crystal. Many exact results have been found for spin 1/2 systems but not for systems of other spins for which many simulation have been carried out. The interest for simulations has been renewed by the Haldane`s conjecture stipulating the existence of a energy gap between the ground state and the first excited states of a spin 1 lattice. The existence of this gap has been experimentally demonstrated. This report contains the following four chapters: 1. Spin systems; 2. Calculation of eigenvalues; 3. Programming; 4. Parallel calculation 14 refs., 6 figs.

  4. Spin Current Noise of the Spin Seebeck Effect and Spin Pumping

    Science.gov (United States)

    Matsuo, M.; Ohnuma, Y.; Kato, T.; Maekawa, S.

    2018-01-01

    We theoretically investigate the fluctuation of a pure spin current induced by the spin Seebeck effect and spin pumping in a normal-metal-(NM-)ferromagnet(FM) bilayer system. Starting with a simple ferromagnet-insulator-(FI-)NM interface model with both spin-conserving and non-spin-conserving processes, we derive general expressions of the spin current and the spin-current noise at the interface within second-order perturbation of the FI-NM coupling strength, and estimate them for a yttrium-iron-garnet-platinum interface. We show that the spin-current noise can be used to determine the effective spin carried by a magnon modified by the non-spin-conserving process at the interface. In addition, we show that it provides information on the effective spin of a magnon, heating at the interface under spin pumping, and spin Hall angle of the NM.

  5. Effect of spin rotation coupling on spin transport

    International Nuclear Information System (INIS)

    Chowdhury, Debashree; Basu, B.

    2013-01-01

    We have studied the spin rotation coupling (SRC) as an ingredient to explain different spin-related issues. This special kind of coupling can play the role of a Dresselhaus like coupling in certain conditions. Consequently, one can control the spin splitting, induced by the Dresselhaus like term, which is unusual in a semiconductor heterostructure. Within this framework, we also study the renormalization of the spin-dependent electric field and spin current due to the k → ⋅p → perturbation, by taking into account the interband mixing in the rotating system. In this paper we predict the enhancement of the spin-dependent electric field resulting from the renormalized spin rotation coupling. The renormalization factor of the spin electric field is different from that of the SRC or Zeeman coupling. The effect of renormalized SRC on spin current and Berry curvature is also studied. Interestingly, in the presence of this SRC-induced SOC it is possible to describe spin splitting as well as spin galvanic effect in semiconductors. -- Highlights: •Studied effect of spin rotation coupling on the spin electric field, spin current and Berry curvature. •In the k → ⋅p → framework we study the renormalization of spin electric field and spin current. •For an inertial system we have discussed the spin splitting. •Expression for the Berry phase in the inertial system is discussed. •The inertial spin galvanic effect is studied

  6. Effect of spin rotation coupling on spin transport

    Energy Technology Data Exchange (ETDEWEB)

    Chowdhury, Debashree, E-mail: debashreephys@gmail.com; Basu, B., E-mail: sribbasu@gmail.com

    2013-12-15

    We have studied the spin rotation coupling (SRC) as an ingredient to explain different spin-related issues. This special kind of coupling can play the role of a Dresselhaus like coupling in certain conditions. Consequently, one can control the spin splitting, induced by the Dresselhaus like term, which is unusual in a semiconductor heterostructure. Within this framework, we also study the renormalization of the spin-dependent electric field and spin current due to the k{sup →}⋅p{sup →} perturbation, by taking into account the interband mixing in the rotating system. In this paper we predict the enhancement of the spin-dependent electric field resulting from the renormalized spin rotation coupling. The renormalization factor of the spin electric field is different from that of the SRC or Zeeman coupling. The effect of renormalized SRC on spin current and Berry curvature is also studied. Interestingly, in the presence of this SRC-induced SOC it is possible to describe spin splitting as well as spin galvanic effect in semiconductors. -- Highlights: •Studied effect of spin rotation coupling on the spin electric field, spin current and Berry curvature. •In the k{sup →}⋅p{sup →} framework we study the renormalization of spin electric field and spin current. •For an inertial system we have discussed the spin splitting. •Expression for the Berry phase in the inertial system is discussed. •The inertial spin galvanic effect is studied.

  7. Spin temperature concept verified by optical magnetometry of nuclear spins

    Science.gov (United States)

    Vladimirova, M.; Cronenberger, S.; Scalbert, D.; Ryzhov, I. I.; Zapasskii, V. S.; Kozlov, G. G.; Lemaître, A.; Kavokin, K. V.

    2018-01-01

    We develop a method of nonperturbative optical control over adiabatic remagnetization of the nuclear spin system and apply it to verify the spin temperature concept in GaAs microcavities. The nuclear spin system is shown to exactly follow the predictions of the spin temperature theory, despite the quadrupole interaction that was earlier reported to disrupt nuclear spin thermalization. These findings open a way for the deep cooling of nuclear spins in semiconductor structures, with the prospect of realizing nuclear spin-ordered states for high-fidelity spin-photon interfaces.

  8. Spin labels. Applications in biology

    International Nuclear Information System (INIS)

    Frangopol, T.P.; Frangopol, M.; Ionescu, S.M.; Pop, I.V.; Benga, G.

    1980-11-01

    The main applications of spin labels in the study of biomembranes, enzymes, nucleic acids, in pharmacology, spin immunoassay are reviewed along with the fundamentals of the spin label method. 137 references. (author)

  9. Spin Switching via Quantum Dot Spin Valves

    Science.gov (United States)

    Gergs, N. M.; Bender, S. A.; Duine, R. A.; Schuricht, D.

    2018-01-01

    We develop a theory for spin transport and magnetization dynamics in a quantum dot spin valve, i.e., two magnetic reservoirs coupled to a quantum dot. Our theory is able to take into account effects of strong correlations. We demonstrate that, as a result of these strong correlations, the dot gate voltage enables control over the current-induced torques on the magnets and, in particular, enables voltage-controlled magnetic switching. The electrical resistance of the structure can be used to read out the magnetic state. Our model may be realized by a number of experimental systems, including magnetic scanning-tunneling microscope tips and artificial quantum dot systems.

  10. Physics lab in spin

    CERN Multimedia

    Hawkes, N

    1999-01-01

    RAL is fostering commerical exploitation of its research and facilities in two main ways : spin-out companies exploit work done at the lab, spin-in companies work on site taking advantage of the facilities and the expertise available (1/2 page).

  11. Summary: Symmetries and spin

    International Nuclear Information System (INIS)

    Haxton, W.C.

    1988-01-01

    I discuss a number of the themes of the Symmetries and Spin session of the 8th International Symposium on High Energy Spin Physics: parity nonconservation, CP/T nonconservation, and tests of charge symmetry and charge independence. 28 refs., 1 fig

  12. Classical spins in superconductors

    Energy Technology Data Exchange (ETDEWEB)

    Shiba, H [Tokyo Univ.; Maki, K

    1968-08-01

    It is shown that there exists a localized excited state in the energy gap in a superconductor with a classical spin. At finite concentration localized excited states around classical spins form an impurity band. The process of growth of the impurity band and its effects on observable quantities are investigated.

  13. More spinoff from spin

    International Nuclear Information System (INIS)

    Masaike, Akira

    1993-01-01

    Despite playing a major role in today's Standard Model, spin - the intrinsic angular momentum carried by particles - is sometimes dismissed as an inessential complication. However several major spin questions with important implications for the Standard Model remain unanswered, and recent results and new technological developments made the 10th International Symposium on High Energy Spin Physics, held in Nagoya, Japan, in November, highly topical. The symposium covered a wide range of physics, reflecting the diversity of spin effects, however four main themes were - the spin content of the nucleon, tests of symmetries and physics beyond standard models, intermediate energy physics, and spin technologies. Opening the meeting, T. Kinoshita reviewed the status of measurements of the anomalous magnetic moment (g-2) of the electron and the muon. The forthcoming experiment at Brookhaven (September 1991, page 23) will probe beyond the energy ranges open to existing electronpositron colliders. For example muon substructure will be opened up to 5 TeV and Ws to 2 TeV. R.L. Jaffe classified quark-parton distributions in terms of their spin dependence, pointing out their leftright attributes, and emphasized the importance of measuring transverse spin distributions through lepton pair production

  14. Introducing optional reserve ratios in Hungary

    OpenAIRE

    Lóránt Varga

    2010-01-01

    As of the reserve maintenance period commencing in November 2010, Hungarian credit institutions will be free to decide whether to apply the previously valid 2% reserve ratio, or to apply a higher mandatory reserve ratio. Credit institutions required to hold reserves may select from reserve ratios of 2, 3, 4 and 5%, and may change their decision on a semi-annual basis. In line with the international best practice, the purpose of the MNB’s reserve requirement system is to support credit institu...

  15. Spin-Wave Diode

    Directory of Open Access Journals (Sweden)

    Jin Lan (兰金

    2015-12-01

    Full Text Available A diode, a device allowing unidirectional signal transmission, is a fundamental element of logic structures, and it lies at the heart of modern information systems. The spin wave or magnon, representing a collective quasiparticle excitation of the magnetic order in magnetic materials, is a promising candidate for an information carrier for the next-generation energy-saving technologies. Here, we propose a scalable and reprogrammable pure spin-wave logic hardware architecture using domain walls and surface anisotropy stripes as waveguides on a single magnetic wafer. We demonstrate theoretically the design principle of the simplest logic component, a spin-wave diode, utilizing the chiral bound states in a magnetic domain wall with a Dzyaloshinskii-Moriya interaction, and confirm its performance through micromagnetic simulations. Our findings open a new vista for realizing different types of pure spin-wave logic components and finally achieving an energy-efficient and hardware-reprogrammable spin-wave computer.

  16. Spin physics at BNL

    International Nuclear Information System (INIS)

    Lowenstein, D.I.

    1985-01-01

    Spin Physics at the Alternating Gradient Synchrotron (AGS) of Brookhaven National Laboratory is the most recent of new capabilities being explored at this facility. During the summer of 1984 the AGS accelerated beams of polarized protons to 16.5 GeV/c at 40% polarization to two experiments (E782, E785). These experiments; single spin asymmetry in inclusive polarized pp interactions; and spin-spin effects in polarized pp elastic scattering, operated at the highest polarized proton energy ever achieved by any accelerator in the world. These experiments are reviewed after the complementary spin physics program with unpolarized protons, and the future possibilities with a booster injector for the AGS and the secondary benefits of a Relativisitic Heavy Ion Collider (RHIC), are placed within the context of the present physics program

  17. Superconductivity and spin fluctuations

    International Nuclear Information System (INIS)

    Scalapino, D.J.

    1999-01-01

    The organizers of the Memorial Session for Herman Rietschel asked that the author review some of the history of the interplay of superconductivity and spin fluctuations. Initially, Berk and Schrieffer showed how paramagnon spin fluctuations could suppress superconductivity in nearly-ferromagnetic materials. Following this, Rietschel and various co-workers wrote a number of papers in which they investigated the role of spin fluctuations in reducing the Tc of various electron-phonon superconductors. Paramagnon spin fluctuations are also believed to provide the p-wave pairing mechanism responsible for the superfluid phases of 3 He. More recently, antiferromagnetic spin fluctuations have been proposed as the mechanism for d-wave pairing in the heavy-fermion superconductors and in some organic materials as well as possibly the high-Tc cuprates. Here the author will review some of this early history and discuss some of the things he has learned more recently from numerical simulations

  18. Spin Hall and spin swapping torques in diffusive ferromagnets

    KAUST Repository

    Pauyac, C. O.

    2017-12-08

    A complete set of the generalized drift-diffusion equations for a coupled charge and spin dynamics in ferromagnets in the presence of extrinsic spin-orbit coupling is derived from the quantum kinetic approach, covering major transport phenomena, such as the spin and anomalous Hall effects, spin swapping, spin precession and relaxation processes. We argue that the spin swapping effect in ferromagnets is enhanced due to spin polarization, while the overall spin texture induced by the interplay of spin-orbital and spin precessional effects displays a complex spatial dependence that can be exploited to generate torques and nucleate/propagate domain walls in centrosymmetric geometries without use of external polarizers, as opposed to the conventional understanding of spin-orbit mediated torques.

  19. Spin Hall and spin swapping torques in diffusive ferromagnets

    KAUST Repository

    Pauyac, C. O.; Chshiev, M.; Manchon, Aurelien; Nikolaev, S. A.

    2017-01-01

    A complete set of the generalized drift-diffusion equations for a coupled charge and spin dynamics in ferromagnets in the presence of extrinsic spin-orbit coupling is derived from the quantum kinetic approach, covering major transport phenomena, such as the spin and anomalous Hall effects, spin swapping, spin precession and relaxation processes. We argue that the spin swapping effect in ferromagnets is enhanced due to spin polarization, while the overall spin texture induced by the interplay of spin-orbital and spin precessional effects displays a complex spatial dependence that can be exploited to generate torques and nucleate/propagate domain walls in centrosymmetric geometries without use of external polarizers, as opposed to the conventional understanding of spin-orbit mediated torques.

  20. HYDROCARBONS RESERVES IN VENEZUELA

    Energy Technology Data Exchange (ETDEWEB)

    Gonzalez Cruz, D.J.

    2007-07-01

    Venezuela is an important player in the energy world, because of its hydrocarbons reserves. The process for calculating oil and associated gas reserves is described bearing in mind that 90% of the gas reserves of Venezuela are associated to oil. Likewise, an analysis is made of the oil reserves figures from 1975 to 2003. Reference is also made to inconsistencies found by international experts and the explanations offered in this respect by the Ministry of Energy and Petroleum (MENPET) and Petroleos de Venezuela (PDVSA) regarding the changes that took place in the 1980s. In turn, Hubbert's Law is explained to determine peak production of conventional oil that a reservoir or field will reach, as well as its relationship with remaining reserves. Emphasis is placed on the interest of the United Nations on this topic. The reserves of associated gas are presented along with their relationship with the different crude oils that are produced and with injected gas, as well as with respect to the possible changes that would take place in the latter if oil reserves are revised. Some recommendations are submitted so that the MENPET starts preparing the pertinent policies ruling reserves. (auth)

  1. Possible signatures of the inflationary particle content: spin-2 fields

    Energy Technology Data Exchange (ETDEWEB)

    Biagetti, Matteo [Institute of Physics, Universiteit van Amsterdam, Science Park, Amsterdam, 1098XH The Netherlands (Netherlands); Dimastrogiovanni, Emanuela [CERCA and Department of Physics, Case Western Reserve University, Cleveland, OH, 44106 (United States); Fasiello, Matteo, E-mail: m.biagetti@uva.nl, E-mail: emanuela1573@gmail.com, E-mail: matteorf@stanford.edu [Stanford Institute for Theoretical Physics and Department of Physics, Stanford University, Stanford, CA, 94306 (United States)

    2017-10-01

    We study the imprints of a massive spin-2 field on inflationary observables, and in particular on the breaking of consistency relations. In this setup, the minimal inflationary field content interacts with the massive spin-2 field through dRGT interactions, thus guaranteeing the absence of Boulware-Deser ghostly degrees of freedom. The unitarity requirement on spinning particles, known as Higuchi bound, plays a crucial role for the size of the observable signal.

  2. Nuclear spin-lattice relaxation in nitroxide spin-label EPR.

    Science.gov (United States)

    Marsh, Derek

    2016-11-01

    Nuclear relaxation is a sensitive monitor of rotational dynamics in spin-label EPR. It also contributes competing saturation transfer pathways in T 1 -exchange spectroscopy, and the determination of paramagnetic relaxation enhancement in site-directed spin labelling. A survey shows that the definition of nitrogen nuclear relaxation rate W n commonly used in the CW-EPR literature for 14 N-nitroxyl spin labels is inconsistent with that currently adopted in time-resolved EPR measurements of saturation recovery. Redefinition of the normalised 14 N spin-lattice relaxation rate, b=W n /(2W e ), preserves the expressions used for CW-EPR, whilst rendering them consistent with expressions for saturation recovery rates in pulsed EPR. Furthermore, values routinely quoted for nuclear relaxation times that are deduced from EPR spectral diffusion rates in 14 N-nitroxyl spin labels do not accord with conventional analysis of spin-lattice relaxation in this three-level system. Expressions for CW-saturation EPR with the revised definitions are summarised. Data on nitrogen nuclear spin-lattice relaxation times are compiled according to the three-level scheme for 14 N-relaxation: T 1 n =1/W n . Results are compared and contrasted with those for the two-level 15 N-nitroxide system. Copyright © 2016 Elsevier Inc. All rights reserved.

  3. Physics and application of persistent spin helix state in semiconductor heterostructures

    Science.gov (United States)

    Kohda, Makoto; Salis, Gian

    2017-07-01

    In order to utilize the spin degree of freedom in semiconductors, control of spin states and transfer of the spin information are fundamental requirements for future spintronic devices and quantum computing. Spin orbit (SO) interaction generates an effective magnetic field for moving electrons and enables spin generation, spin manipulation and spin detection without using external magnetic field and magnetic materials. However, spin relaxation also takes place due to a momentum dependent SO-induced effective magnetic field. As a result, SO interaction is considered to be a double-edged sword facilitating spin control but preventing spin transport over long distances. The persistent spin helix (PSH) state solves this problem since uniaxial alignment of the SO field with SU(2) symmetry enables the suppression of spin relaxation while spin precession can still be controlled. Consequently, understanding the PSH becomes an important step towards future spintronic technologies for classical and quantum applications. Here, we review recent progress of PSH in semiconductor heterostructures and its device application. Fundamental physics of SO interaction and the conditions of a PSH state in semiconductor heterostructures are discussed. We introduce experimental techniques to observe a PSH and explain both optical and electrical measurements for detecting a long spin relaxation time and the formation of a helical spin texture. After emphasizing the bulk Dresselhaus SO coefficient γ, the application of PSH states for spin transistors and logic circuits are discussed.

  4. Spin-Wave Wave Function for Quantum Spin Models : Condensed Matter and Statistical Physics

    OpenAIRE

    Franjo, FRANJIC; Sandro, SORELLA; Istituto Nazionale di Fisica della Materia International School for Advance Studies; Istituto Nazionale di Fisica della Materia International School for Advance Studies

    1997-01-01

    We present a new approach to determine an accurate variational wave function for general quantum spin models, completely defined by a consistency requirement with the simple and well-known linear spin-wave expansion. With this wave function, it is also possible to obtain the correct behavior of the long distance correlation functions for the 1D S=1/2 antiferromagnet. In 2D the proposed spin-wave wave function represents an excellent approximation to the exact ground state of the S=1.2 XY mode...

  5. Resonant Tunneling Spin Pump

    Science.gov (United States)

    Ting, David Z.

    2007-01-01

    The resonant tunneling spin pump is a proposed semiconductor device that would generate spin-polarized electron currents. The resonant tunneling spin pump would be a purely electrical device in the sense that it would not contain any magnetic material and would not rely on an applied magnetic field. Also, unlike prior sources of spin-polarized electron currents, the proposed device would not depend on a source of circularly polarized light. The proposed semiconductor electron-spin filters would exploit the Rashba effect, which can induce energy splitting in what would otherwise be degenerate quantum states, caused by a spin-orbit interaction in conjunction with a structural-inversion asymmetry in the presence of interfacial electric fields in a semiconductor heterostructure. The magnitude of the energy split is proportional to the electron wave number. Theoretical studies have suggested the possibility of devices in which electron energy states would be split by the Rashba effect and spin-polarized currents would be extracted by resonant quantum-mechanical tunneling.

  6. Nuclear spins in nanostructures

    International Nuclear Information System (INIS)

    Coish, W.A.; Baugh, J.

    2009-01-01

    We review recent theoretical and experimental advances toward understanding the effects of nuclear spins in confined nanostructures. These systems, which include quantum dots, defect centers, and molecular magnets, are particularly interesting for their importance in quantum information processing devices, which aim to coherently manipulate single electron spins with high precision. On one hand, interactions between confined electron spins and a nuclear-spin environment provide a decoherence source for the electron, and on the other, a strong effective magnetic field that can be used to execute local coherent rotations. A great deal of effort has been directed toward understanding the details of the relevant decoherence processes and to find new methods to manipulate the coupled electron-nuclear system. A sequence of spectacular new results have provided understanding of spin-bath decoherence, nuclear spin diffusion, and preparation of the nuclear state through dynamic polarization and more general manipulation of the nuclear-spin density matrix through ''state narrowing.'' These results demonstrate the richness of this physical system and promise many new mysteries for the future. (Abstract Copyright [2009], Wiley Periodicals, Inc.)

  7. Spin drift and spin diffusion currents in semiconductors

    Energy Technology Data Exchange (ETDEWEB)

    Idrish Miah, M [Nanoscale Science and Technology Centre and School of Biomolecular and Physical Sciences, Griffith University, Nathan, Brisbane, QLD 4111 (Australia)], E-mail: m.miah@griffith.edu.au

    2008-09-15

    On the basis of a spin drift-diffusion model, we show how the spin current is composed and find that spin drift and spin diffusion contribute additively to the spin current, where the spin diffusion current decreases with electric field while the spin drift current increases, demonstrating that the extension of the spin diffusion length by a strong field does not result in a significant increase in spin current in semiconductors owing to the competing effect of the electric field on diffusion. We also find that there is a spin drift-diffusion crossover field for a process in which the drift and diffusion contribute equally to the spin current, which suggests a possible method of identifying whether the process for a given electric field is in the spin drift or spin diffusion regime. Spin drift-diffusion crossover fields for GaAs are calculated and are found to be quite small. We derive the relations between intrinsic spin diffusion length and the spin drift-diffusion crossover field of a semiconductor for different electron statistical regimes. The findings resulting from this investigation might be important for semiconductor spintronics.

  8. Spin drift and spin diffusion currents in semiconductors

    Directory of Open Access Journals (Sweden)

    M Idrish Miah

    2008-01-01

    Full Text Available On the basis of a spin drift-diffusion model, we show how the spin current is composed and find that spin drift and spin diffusion contribute additively to the spin current, where the spin diffusion current decreases with electric field while the spin drift current increases, demonstrating that the extension of the spin diffusion length by a strong field does not result in a significant increase in spin current in semiconductors owing to the competing effect of the electric field on diffusion. We also find that there is a spin drift-diffusion crossover field for a process in which the drift and diffusion contribute equally to the spin current, which suggests a possible method of identifying whether the process for a given electric field is in the spin drift or spin diffusion regime. Spin drift-diffusion crossover fields for GaAs are calculated and are found to be quite small. We derive the relations between intrinsic spin diffusion length and the spin drift-diffusion crossover field of a semiconductor for different electron statistical regimes. The findings resulting from this investigation might be important for semiconductor spintronics.

  9. Spin drift and spin diffusion currents in semiconductors

    International Nuclear Information System (INIS)

    Idrish Miah, M

    2008-01-01

    On the basis of a spin drift-diffusion model, we show how the spin current is composed and find that spin drift and spin diffusion contribute additively to the spin current, where the spin diffusion current decreases with electric field while the spin drift current increases, demonstrating that the extension of the spin diffusion length by a strong field does not result in a significant increase in spin current in semiconductors owing to the competing effect of the electric field on diffusion. We also find that there is a spin drift-diffusion crossover field for a process in which the drift and diffusion contribute equally to the spin current, which suggests a possible method of identifying whether the process for a given electric field is in the spin drift or spin diffusion regime. Spin drift-diffusion crossover fields for GaAs are calculated and are found to be quite small. We derive the relations between intrinsic spin diffusion length and the spin drift-diffusion crossover field of a semiconductor for different electron statistical regimes. The findings resulting from this investigation might be important for semiconductor spintronics.

  10. Quantifying Spin Hall Angles from Spin Pumping : Experiments and Theory

    NARCIS (Netherlands)

    Mosendz, O.; Pearson, J.E.; Fradin, F.Y.; Bauer, G.E.W.; Bader, S.D.; Hoffmann, A.

    2010-01-01

    Spin Hall effects intermix spin and charge currents even in nonmagnetic materials and, therefore, ultimately may allow the use of spin transport without the need for ferromagnets. We show how spin Hall effects can be quantified by integrating Ni80Fe20|normal metal (N) bilayers into a coplanar

  11. Compound nucleus effects in spin-spin cross sections

    International Nuclear Information System (INIS)

    Thompson, W.J.

    1976-01-01

    By comparison with recent data, it is shown that spin-spin cross sections for low-energy neutrons may be dominated by a simple compound-elastic level-density effect, independent of spin-spin terms in the nucleon-nucleus optical-model potential. (Auth.)

  12. A new multi-objective reserve constrained combined heat and power dynamic economic emission dispatch

    International Nuclear Information System (INIS)

    Niknam, Taher; Azizipanah-Abarghooee, Rasoul; Roosta, Alireza; Amiri, Babak

    2012-01-01

    Combined heat and power units are playing an ever increasing role in conventional power stations due to advantages such as reduced emissions and operational cost savings. This paper investigates a more practical formulation of the complex non-convex, non-smooth and non-linear multi-objective dynamic economic emission dispatch that incorporates combined heat and power units. Integrating these types of units, and their power ramp constraints, require an efficient tool to cope with the joint characteristics of power and heat. Unlike previous approaches, the spinning reserve requirements of this system are clearly formulated in the problem. In this way, a new multi-objective optimisation based on an enhanced firefly algorithm is proposed to achieve a set of non-dominated (Pareto-optimal) solutions. A new tuning parameter based on a chaotic mechanism and novel self adaptive probabilistic mutation strategies are used to improve the overall performance of the algorithm. The numerical results demonstrate how the proposed framework was applied in real time studies. -- Highlights: ► Investigate a practical formulation of the DEED (Dynamic Economic Emission Dispatch). ► Consider combined heat and power units. ► Consider power ramp constraints. ► Consider the system spinning reserve requirements. ► Present a new multi-objective optimization firefly.

  13. Frustrated spin systems

    CERN Document Server

    2013-01-01

    This book covers all principal aspects of currently investigated frustrated systems, from exactly solved frustrated models to real experimental frustrated systems, going through renormalization group treatment, Monte Carlo investigation of frustrated classical Ising and vector spin models, low-dimensional systems, spin ice and quantum spin glass. The reader can - within a single book - obtain a global view of the current research development in the field of frustrated systems.This new edition is updated with recent theoretical, numerical and experimental developments in the field of frustrated

  14. SPINning parallel systems software

    International Nuclear Information System (INIS)

    Matlin, O.S.; Lusk, E.; McCune, W.

    2002-01-01

    We describe our experiences in using Spin to verify parts of the Multi Purpose Daemon (MPD) parallel process management system. MPD is a distributed collection of processes connected by Unix network sockets. MPD is dynamic processes and connections among them are created and destroyed as MPD is initialized, runs user processes, recovers from faults, and terminates. This dynamic nature is easily expressible in the Spin/Promela framework but poses performance and scalability challenges. We present here the results of expressing some of the parallel algorithms of MPD and executing both simulation and verification runs with Spin

  15. Spins in chemistry

    CERN Document Server

    McWeeny, Roy

    2004-01-01

    Originally delivered as a series of lectures, this volume systematically traces the evolution of the ""spin"" concept from its role in quantum mechanics to its assimilation into the field of chemistry. Author Roy McWeeny presents an in-depth illustration of the deductive methods of quantum theory and their application to spins in chemistry, following the path from the earliest concepts to the sophisticated physical methods employed in the investigation of molecular structure and properties. Starting with the origin and development of the spin concept, the text advances to an examination of sp

  16. NUCLEON SPIN: Enigma confirmed

    International Nuclear Information System (INIS)

    Anon.

    1994-01-01

    In 1987 the European Muon Collaboration (EMC - June 1988, page 9) reported results from a polarized muon-proton scattering experiment at CERN which puzzled the particle and nuclear physics communities. Contrary to the prediction of the naive quark model, the EMC found that little of the proton spin seemed to be carried by the spins of the quarks. An extensive experimental programme was therefore immediately proposed at CERN, SLAC (Stanford) and DESY (Hamburg) to measure the spin structure function of the neutron and to repeat the proton measurement with improved accuracy

  17. Spin-polarized SEM

    International Nuclear Information System (INIS)

    Konoto, Makoto

    2007-01-01

    Development of highly effective evaluation technology of magnetic structures on a nanometric scale is a key to understanding spintronics and related phenomena. A high-resolution spin-polarized scanning electron microscope (spin SEM) developed recently is quite suitable for probing such nanostructures because of the capability of analyzing local magnetization vectors in three dimensions. Utilizing the spin SEM, a layered antiferromagnetic structure with the 1nm-alternation of bilayer-sheet magnetization has been successfully resolved. The real-space imaging with full analysis of the temperature-dependent magnetization vectors will be demonstrated. (author)

  18. High spin structure functions

    International Nuclear Information System (INIS)

    Khan, H.

    1990-01-01

    This thesis explores deep inelastic scattering of a lepton beam from a polarized nuclear target with spin J=1. After reviewing the formation for spin-1/2, the structure functions for a spin-1 target are defined in terms of the helicity amplitudes for forward compton scattering. A version of the convolution model, which incorporates relativistic and binding energy corrections is used to calculate the structure functions of a neutron target. A simple parameterization of these structure functions is given in terms of a few neutron wave function parameters and the free nucleon structure functions. This allows for an easy comparison of structure functions calculated using different neutron models. (author)

  19. Spin Hall effect transistor

    Czech Academy of Sciences Publication Activity Database

    Wunderlich, Joerg; Park, B.G.; Irvine, A.C.; Zarbo, Liviu; Rozkotová, E.; Němec, P.; Novák, Vít; Sinova, Jairo; Jungwirth, Tomáš

    2010-01-01

    Roč. 330, č. 6012 (2010), s. 1801-1804 ISSN 0036-8075 R&D Projects: GA AV ČR KAN400100652; GA MŠk LC510 EU Projects: European Commission(XE) 215368 - SemiSpinNet Grant - others:AV ČR(CZ) AP0801 Program:Akademická prémie - Praemium Academiae Institutional research plan: CEZ:AV0Z10100521 Keywords : spin Hall effect * spintronics * spin transistor Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 31.364, year: 2010

  20. Spinning of refractory metals

    International Nuclear Information System (INIS)

    Chang Wenkua; Zheng Han

    1989-01-01

    The effects of spinning process parameters including max. pass percentage reduction, spinning temperature, feed rate, lubricant and annealing technology on the quality of shaped components are summarized and discussed in the present paper. The above mentioned parameters are adopted in the process of spinning of barrel-shaped and specially shaped components of refractory metals and their alloys W, Mo, Nb, Zr, TZM molybdenum alloy, C-103, C-752 niobium alloy etc. The cause of leading to usual defects of spun products of refractory metals such as lamellar as 'scaling', crack, swelling, wrinkle, etc. have been analysed and the ways to eliminate the defects have been put forward. 8 figs., 5 tabs. (Author)

  1. Skyline Reservation System

    Data.gov (United States)

    US Agency for International Development — Flight reservation application used for in-country flights by USAID and DoS staff in Afghanistan. The application is managed and maintained by the vendor and USAID...

  2. Spin transfer torque with spin diffusion in magnetic tunnel junctions

    KAUST Repository

    Manchon, Aurelien

    2012-08-09

    Spin transport in magnetic tunnel junctions in the presence of spin diffusion is considered theoretically. Combining ballistic tunneling across the barrier and diffusive transport in the electrodes, we solve the spin dynamics equation in the metallic layers. We show that spin diffusion mixes the transverse spin current components and dramatically modifies the bias dependence of the effective spin transfer torque. This leads to a significant linear bias dependence of the out-of-plane torque, as well as a nonconventional thickness dependence of both spin torque components.

  3. Electron spin and nuclear spin manipulation in semiconductor nanosystems

    International Nuclear Information System (INIS)

    Hirayama, Yoshiro; Yusa, Go; Sasaki, Satoshi

    2006-01-01

    Manipulations of electron spin and nuclear spin have been studied in AlGaAs/GaAs semiconductor nanosystems. Non-local manipulation of electron spins has been realized by using the correlation effect between localized and mobile electron spins in a quantum dot- quantum wire coupled system. Interaction between electron and nuclear spins was exploited to achieve a coherent control of nuclear spins in a semiconductor point contact device. Using this device, we have demonstrated a fully coherent manipulation of any two states among the four spin levels of Ga and As nuclei. (copyright 2006 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  4. In search of elementary spin 0 particles

    International Nuclear Information System (INIS)

    Krasny, Mieczyslaw Witold; Płaczek, Wiesław

    2015-01-01

    The Standard Model of strong and electroweak interactions uses point-like spin 1/2 particles as the building bricks of matter and point-like spin 1 particles as the force carriers. One of the most important questions to be answered by the present and future particle physics experiments is whether the elementary spin 0 particles exist, and if they do, what are their interactions with the spin 1/2 and spin 1 particles. Spin 0 particles have been searched extensively over the last decades. Several initial claims of their discoveries were finally disproved in the final experimental scrutiny process. The recent observation of the excess of events at the LHC in the final states involving a pair of vector bosons, or photons, is commonly interpreted as the discovery of the first elementary scalar particle, the Higgs boson. In this paper we recall examples of claims and subsequent disillusions in precedent searches spin 0 particles. We address the question if the LHC Higgs discovery can already be taken for granted, or, as it turned out important in the past, whether it requires a further experimental scrutiny before the existence of the first ever found elementary scalar particle is proven beyond any doubt. An example of the Double Drell–Yan process for which such a scrutiny is indispensable is discussed in some detail. - Highlights: • We present a short history of searches of spin 0 particles. • We construct a model of the Double Drell–Yan Process (DDYP) at the LHC. • We investigate the contribution of the DDYP to the Higgs searches background

  5. When measured spin polarization is not spin polarization

    International Nuclear Information System (INIS)

    Dowben, P A; Wu Ning; Binek, Christian

    2011-01-01

    Spin polarization is an unusually ambiguous scientific idiom and, as such, is rarely well defined. A given experimental methodology may allow one to quantify a spin polarization but only in its particular context. As one might expect, these ambiguities sometimes give rise to inappropriate interpretations when comparing the spin polarizations determined through different methods. The spin polarization of CrO 2 and Cr 2 O 3 illustrate some of the complications which hinders comparisons of spin polarization values. (viewpoint)

  6. 24 CFR 891.745 - Replacement reserve.

    Science.gov (United States)

    2010-04-01

    ... 24 Housing and Urban Development 4 2010-04-01 2010-04-01 false Replacement reserve. 891.745... and Individuals-Section 162 Assistance § 891.745 Replacement reserve. The general requirements for the replacement reserve are provided in § 891.605. For projects funded under §§ 891.655 through 891.790, the...

  7. 24 CFR 572.125 - Replacement reserves.

    Science.gov (United States)

    2010-04-01

    ...) Homeownership Program Requirements-Implementation Grants § 572.125 Replacement reserves. (a) Purpose. A single replacement reserve may be established for the homeownership program only if HUD determines it is necessary to... 24 Housing and Urban Development 3 2010-04-01 2010-04-01 false Replacement reserves. 572.125...

  8. Spin dynamics in electron synchrotrons; Spindynamik in Elektronensynchrotronen

    Energy Technology Data Exchange (ETDEWEB)

    Schmidt, Jan Felix

    2017-07-14

    Providing spin polarized particle beams with circular accelerators requires the consideration of depolarizing resonances which may significantly reduce the desired degree of polarization at specific beam energies. The corresponding spin dynamical effects are typically analyzed with numerical methods. In case of electron beams the influence of the emission of synchrotron radiation has to be taken into account. On short timescales, as in synchrotrons with a fast energy ramp or in damping rings, spin dynamics are investigated with spin tracking algorithms. This thesis presents the spin tracking code Polematrix as a versatile tool to study the impact of synchrotron radiation on spin dynamics. Spin tracking simulations have been performed based on the well established particle tracking code Elegant. The numerical studies demonstrate effects which are responsible for beam depolarization: Synchrotron side bands of depolarizing resonances and decoherence of spin precession. Polematrix can be utilized for any electron accelerator with minimal effort as it imports lattice files from the tracking programs MAD-X or Elegant. Polematrix has been published as open source software. Currently, the Electron Stretcher Accelerator ELSA at Bonn University is the only electron synchrotron worldwide providing a polarized beam. Integer and intrinsic depolarizing resonances are compensated with dedicated countermeasures during the fast energy ramp. Polarization measurements from ELSA demonstrate the particular spin dynamics of electrons and confirm the results of the spin tracking code Polematrix.

  9. Anisotropic spin relaxation in graphene

    NARCIS (Netherlands)

    Tombros, N.; Tanabe, S.; Veligura, A.; Jozsa, C.; Popinciuc, M.; Jonkman, H. T.; van Wees, B. J.

    2008-01-01

    Spin relaxation in graphene is investigated in electrical graphene spin valve devices in the nonlocal geometry. Ferromagnetic electrodes with in-plane magnetizations inject spins parallel to the graphene layer. They are subject to Hanle spin precession under a magnetic field B applied perpendicular

  10. Spin squeezing and quantum correlations

    Indian Academy of Sciences (India)

    2 states. A coherent spin-s state. (CSS) θ φ can then be thought of as having no quantum correlations as the constituent. 2s elementary spins point in the same direction ˆn(θ φ) which is the mean spin direction. 2. State classification and squeezing. In order to discuss squeezing, we begin with the squeezing condition itself.

  11. Geometry of spin coherent states

    Science.gov (United States)

    Chryssomalakos, C.; Guzmán-González, E.; Serrano-Ensástiga, E.

    2018-04-01

    Spin states of maximal projection along some direction in space are called (spin) coherent, and are, in many respects, the ‘most classical’ available. For any spin s, the spin coherent states form a 2-sphere in the projective Hilbert space \

  12. Probing Spin Crossover in a Solution by Paramagnetic NMR Spectroscopy.

    Science.gov (United States)

    Pavlov, Alexander A; Denisov, Gleb L; Kiskin, Mikhail A; Nelyubina, Yulia V; Novikov, Valentin V

    2017-12-18

    Spin transitions in spin-crossover compounds are now routinely studied in the solid state by magnetometry; however, only a few methods exist for studies in solution. The currently used Evans method, which relies on NMR spectroscopy to measure the magnetic susceptibility, requires the availability of a very pure sample of the paramagnetic compound and its exact concentration. To overcome these limitations, we propose an alternative NMR-based technique for evaluating spin-state populations by only using the chemical shifts of a spin-crossover compound; those can be routinely obtained for a solution that contains unknown impurities and paramagnetic admixtures or is contaminated otherwise.

  13. Assisted Writing in Spin Transfer Torque Magnetic Tunnel Junctions

    Science.gov (United States)

    Ganguly, Samiran; Ahmed, Zeeshan; Datta, Supriyo; Marinero, Ernesto E.

    2015-03-01

    Spin transfer torque driven MRAM devices are now in an advanced state of development, and the importance of reducing the current requirement for writing information is well recognized. Different approaches to assist the writing process have been proposed such as spin orbit torque, spin Hall effect, voltage controlled magnetic anisotropy and thermal excitation. In this work,we report on our comparative study using the Spin-Circuit Approach regarding the total energy, the switching speed and energy-delay products for different assisted writing approaches in STT-MTJ devices using PMA magnets.

  14. Internal Spin Control, Squeezing and Decoherence in Ensembles of Alkali Atomic Spins

    Science.gov (United States)

    Norris, Leigh Morgan

    Large atomic ensembles interacting with light are one of the most promising platforms for quantum information processing. In the past decade, novel applications for these systems have emerged in quantum communication, quantum computing, and metrology. Essential to all of these applications is the controllability of the atomic ensemble, which is facilitated by a strong coupling between the atoms and light. Non-classical spin squeezed states are a crucial step in attaining greater ensemble control. The degree of entanglement present in these states, furthermore, serves as a benchmark for the strength of the atom-light interaction. Outside the broader context of quantum information processing with atomic ensembles, spin squeezed states have applications in metrology, where their quantum correlations can be harnessed to improve the precision of magnetometers and atomic clocks. This dissertation focuses upon the production of spin squeezed states in large ensembles of cold trapped alkali atoms interacting with optical fields. While most treatments of spin squeezing consider only the case in which the ensemble is composed of two level systems or qubits, we utilize the entire ground manifold of an alkali atom with hyperfine spin f greater than or equal to 1/2, a qudit. Spin squeezing requires non-classical correlations between the constituent atomic spins, which are generated through the atoms' collective coupling to the light. Either through measurement or multiple interactions with the atoms, the light mediates an entangling interaction that produces quantum correlations. Because the spin squeezing treated in this dissertation ultimately originates from the coupling between the light and atoms, conventional approaches of improving this squeezing have focused on increasing the optical density of the ensemble. The greater number of internal degrees of freedom and the controllability of the spin-f ground hyperfine manifold enable novel methods of enhancing squeezing. In

  15. US uranium reserves

    International Nuclear Information System (INIS)

    Hansen, M.V.

    1981-01-01

    The current low level of demand, compounded by rapidly rising costs and low prices, has caused a significant reduction in drilling for uranium in the United States, and the trend is likely to continue for a few more years. The effect on uranium reserves will be fewer additions to reserves because less exploration is being done. Further reductions will occur, especially in low-cost reserves, because of increasing costs, continuing depletion through production, and erosion through the high grading of deposits to fulfill previous contractual commitments. During the past several years, it has been necessary to increase the upper reserve cost level twice to compensate for rising costs. Rising costs are reducing the $15 reserves, the cost category corresponding most closely to the present market price, to an insignificant level. An encouraging factor related to US uranium reserves is that the US position internationally, as far as quantity is concerned, is not bad for the longer term. Also, there is a general opinion that US consumers would rather contract for domestic uranium than for foreign because of greater assurance of supply. Still another factor, nearly impossible to assess, is what effect rising costs in other countries will have on their uranium reserves. The annual conferences between the Grand Junction Area Office staff and major uranium companies provide a broad overview of the industry's perception of the future. It is not optimistic for the short term. Many companies are reducing their exploration and mining programs; some are switching to other more marketable mineral commodities, and a few are investing more heavily in foreign ventures. However, there is general optimism for the long term, and many predict a growth in demand in the mid-1980s. If the industry can survive the few lean years ahead, rising prices may restore its viability to former levels

  16. Terwilliger and spin physics

    International Nuclear Information System (INIS)

    O'FAllon, J.R.

    1991-01-01

    The history of spin physics experiments is presented, with emphasis of Kent Terwilliger's involvement. Development of polarized beams and targets at the ZGS and AGS is recalled. P-P elastic scattering experiments are reviewed

  17. Transverse spin effects

    International Nuclear Information System (INIS)

    Ratcliffe, P.G.

    1993-01-01

    A discussion is presented of the role that transverse spin physics can play in providing information on the bound state dynamics in hadronic physics. Care is taken to distinguish between single- and double-spin measurements, each being discussed separately. In the case of single-spin effects it is stressed that as yet no satisfactory explanation has been provided within the framework if perturbative QCD which in fact generally predicts negligible effects. In order to clarify the situation experimental data at yet higher p T are necessary and semi-leptonic data could shed some light on the underlying scattering mechanisms. As regards double-spin correlations, the theoretical picture (although clouded by some ill-informed, often erroneous statements and even recent papers) is rather well understood and what is dearly missing is the experimental study of, for example, g 2 in deep-inelastic scattering. (author). 31 refs

  18. Spin polarized deuterium

    International Nuclear Information System (INIS)

    Glyde, H.R.; Hernadi, S.I.

    1986-01-01

    Several ground state properties of (electron) spin-polarized deuterium (D) such as the energy, single quasiparticle energies and lifetimes, Landau parameters and sound velocities are evaluated. The calculations begin with the Kolos-Wolneiwicz potential and use the Galitskii-FeynmanHartree-Fock (GFHF) approximation. The deuteron nucleas has spin I = 1, and spin states I/sub z/ = 1,0,-1. We explore D 1 , D 2 and D 3 in which, respectively, one spin state only is populated, two states are equally populated, and three states are equally populated. We find the GFHF describes D 1 well, but D 2 and D 3 less well. The Landau parameters, F/sub L/, are small compared to liquid 3 He and very small for doubly polarized D 1 (i.e. the F/sub L/ decrease with nuclear polarization)

  19. Current-Induced Spin Polarization at a Single Heterojunction

    NARCIS (Netherlands)

    Silov, A.; Blajnov, P.; Wolter, J.H.; Hey, R.; Ploog, K.; Averkiev, N.S.; Menendez, J.; Walle, van der C.G.

    2005-01-01

    We have experimentally achieved spin-polarization by a lateral current in a single non-magnetic semiconductor heterojunction. The effect does not require an applied magnetic field or ferromagnetic contacts. The current-induced spin orientation can be seen as the inverse of the circular

  20. Gravitational Waves and the Maximum Spin Frequency of Neutron Stars

    NARCIS (Netherlands)

    Patruno, A.; Haskell, B.; D'Angelo, C.

    2012-01-01

    In this paper, we re-examine the idea that gravitational waves are required as a braking mechanism to explain the observed maximum spin frequency of neutron stars. We show that for millisecond X-ray pulsars, the existence of spin equilibrium as set by the disk/magnetosphere interaction is sufficient

  1. Microscopic studies of nonlocal spin dynamics and spin transport (invited)

    Energy Technology Data Exchange (ETDEWEB)

    Adur, Rohan; Du, Chunhui; Cardellino, Jeremy; Scozzaro, Nicolas; Wolfe, Christopher S.; Wang, Hailong; Herman, Michael; Bhallamudi, Vidya P.; Pelekhov, Denis V.; Yang, Fengyuan; Hammel, P. Chris, E-mail: hammel@physics.osu.edu [Department of Physics, The Ohio State University, Columbus, Ohio 43210 (United States)

    2015-05-07

    Understanding the behavior of spins coupling across interfaces in the study of spin current generation and transport is a fundamental challenge that is important for spintronics applications. The transfer of spin angular momentum from a ferromagnet into an adjacent normal material as a consequence of the precession of the magnetization of the ferromagnet is a process known as spin pumping. We find that, in certain circumstances, the insertion of an intervening normal metal can enhance spin pumping between an excited ferromagnetic magnetization and a normal metal layer as a consequence of improved spin conductance matching. We have studied this using inverse spin Hall effect and enhanced damping measurements. Scanned probe magnetic resonance techniques are a complementary tool in this context offering high resolution magnetic resonance imaging, localized spin excitation, and direct measurement of spin lifetimes or damping. Localized magnetic resonance studies of size-dependent spin dynamics in the absence of lithographic confinement in both ferromagnets and paramagnets reveal the close relationship between spin transport and spin lifetime at microscopic length scales. Finally, detection of ferromagnetic resonance of a ferromagnetic film using the photoluminescence of nitrogen vacancy spins in neighboring nanodiamonds demonstrates long-range spin transport between insulating materials, indicating the complexity and generality of spin transport in diverse, spatially separated, material systems.

  2. Microscopic studies of nonlocal spin dynamics and spin transport (invited)

    Science.gov (United States)

    Adur, Rohan; Du, Chunhui; Cardellino, Jeremy; Scozzaro, Nicolas; Wolfe, Christopher S.; Wang, Hailong; Herman, Michael; Bhallamudi, Vidya P.; Pelekhov, Denis V.; Yang, Fengyuan; Hammel, P. Chris

    2015-05-01

    Understanding the behavior of spins coupling across interfaces in the study of spin current generation and transport is a fundamental challenge that is important for spintronics applications. The transfer of spin angular momentum from a ferromagnet into an adjacent normal material as a consequence of the precession of the magnetization of the ferromagnet is a process known as spin pumping. We find that, in certain circumstances, the insertion of an intervening normal metal can enhance spin pumping between an excited ferromagnetic magnetization and a normal metal layer as a consequence of improved spin conductance matching. We have studied this using inverse spin Hall effect and enhanced damping measurements. Scanned probe magnetic resonance techniques are a complementary tool in this context offering high resolution magnetic resonance imaging, localized spin excitation, and direct measurement of spin lifetimes or damping. Localized magnetic resonance studies of size-dependent spin dynamics in the absence of lithographic confinement in both ferromagnets and paramagnets reveal the close relationship between spin transport and spin lifetime at microscopic length scales. Finally, detection of ferromagnetic resonance of a ferromagnetic film using the photoluminescence of nitrogen vacancy spins in neighboring nanodiamonds demonstrates long-range spin transport between insulating materials, indicating the complexity and generality of spin transport in diverse, spatially separated, material systems.

  3. Microscopic studies of nonlocal spin dynamics and spin transport (invited)

    International Nuclear Information System (INIS)

    Adur, Rohan; Du, Chunhui; Cardellino, Jeremy; Scozzaro, Nicolas; Wolfe, Christopher S.; Wang, Hailong; Herman, Michael; Bhallamudi, Vidya P.; Pelekhov, Denis V.; Yang, Fengyuan; Hammel, P. Chris

    2015-01-01

    Understanding the behavior of spins coupling across interfaces in the study of spin current generation and transport is a fundamental challenge that is important for spintronics applications. The transfer of spin angular momentum from a ferromagnet into an adjacent normal material as a consequence of the precession of the magnetization of the ferromagnet is a process known as spin pumping. We find that, in certain circumstances, the insertion of an intervening normal metal can enhance spin pumping between an excited ferromagnetic magnetization and a normal metal layer as a consequence of improved spin conductance matching. We have studied this using inverse spin Hall effect and enhanced damping measurements. Scanned probe magnetic resonance techniques are a complementary tool in this context offering high resolution magnetic resonance imaging, localized spin excitation, and direct measurement of spin lifetimes or damping. Localized magnetic resonance studies of size-dependent spin dynamics in the absence of lithographic confinement in both ferromagnets and paramagnets reveal the close relationship between spin transport and spin lifetime at microscopic length scales. Finally, detection of ferromagnetic resonance of a ferromagnetic film using the photoluminescence of nitrogen vacancy spins in neighboring nanodiamonds demonstrates long-range spin transport between insulating materials, indicating the complexity and generality of spin transport in diverse, spatially separated, material systems

  4. Exertional Rhabdomyolysis after Spinning

    OpenAIRE

    Jeong, Youjin; Kweon, Hyuk-Jung; Oh, Eun-Jung; Ahn, Ah-Leum; Choi, Jae-Kyung; Cho, Dong-Yung

    2016-01-01

    Any strenuous muscular exercise may trigger rhabdomyolysis. We report an episode of clinically manifested exertional rhabdomyolysis due to stationary cycling, commonly known as spinning. Reports of spinning-related rhabdomyolysis are rare in the English literature, and the current case appears to be the first such case reported in South Korea. A previously healthy 21-year-old Asian woman presented with severe thigh pain and reddish-brown urinary discoloration 24?48 hours after attending a spi...

  5. Higher Spins & Strings

    CERN Multimedia

    CERN. Geneva

    2014-01-01

    The conjectured relation between higher spin theories on anti de-Sitter (AdS) spaces and weakly coupled conformal field theories is reviewed. I shall then outline the evidence in favour of a concrete duality of this kind, relating a specific higher spin theory on AdS3 to a family of 2d minimal model CFTs. Finally, I shall explain how this relation fits into the framework of the familiar stringy AdS/CFT correspondence.

  6. Spin interactions in Graphene-Single Molecule Magnets Hybrids

    Science.gov (United States)

    Cervetti, Christian; Rettori, Angelo; Pini, Maria Gloria; Cornia, Andrea; Repollés, Aña; Luis, Fernando; Rauschenbach, Stephan; Dressel, Martin; Kern, Klaus; Burghard, Marko; Bogani, Lapo

    2014-03-01

    Graphene is a potential component of novel spintronics devices owing to its long spin diffusion length. Besides its use as spin-transport channel, graphene can be employed for the detection and manipulation of molecular spins. This requires an appropriate coupling between the sheets and the single molecular magnets (SMM). Here, we present a comprehensive characterization of graphene-Fe4 SMM hybrids. The Fe4 clusters are anchored non-covalently to the graphene following a diffusion-limited assembly and can reorganize into random networks when subjected to slightly elevated temperature. Molecules anchored on graphene sheets show unaltered static magnetic properties, whilst the quantum dynamics is profoundly modulated. Interaction with Dirac fermions becomes the dominant spin-relaxation channel, with observable effects produced by graphene phonons and reduced dipolar interactions. Coupling to graphene drives the spins over Villain's threshold, allowing the first observation of strongly-perturbative tunneling processes. Preliminary spin-transport experiments at low-temperature are further presented.

  7. Electrical spin injection into high mobility 2D systems.

    Science.gov (United States)

    Oltscher, M; Ciorga, M; Utz, M; Schuh, D; Bougeard, D; Weiss, D

    2014-12-05

    We report on spin injection into a high mobility 2D electron system confined at an (Al,Ga)As/GaAs interface, using (Ga,Mn)As Esaki diode contacts as spin aligners. We measured a clear nonlocal spin valve signal, which varies nonmonotonically with the applied bias voltage. The magnitude of the signal cannot be described by the standard spin drift-diffusion model, because at maximum this would require the spin polarization of the injected current to be much larger than 100%, which is unphysical. A strong correlation of the spin signal with contact width and electron mean free path suggests that ballistic transport in the 2D region below ferromagnetic contacts should be taken into account to fully describe the results.

  8. The Army's Commitment to Supporting the Homeland Security Chemical, Biological, Radiological, Nuclear, and High-Yield Explosive Weapon Terrorist Threat: Can the Reserve Components Meet the Requirement by Themselves

    National Research Council Canada - National Science Library

    Anderson, Donnie

    2001-01-01

    .... Specifically, it will address the Reserve Components (RC) capability for responding to an incident and demonstrate the value-added of Active Component (AC) forces. The conclusion is the RC cannot fulfill the Department of the Army's commitment to this important mission by itself: AC forces must assume a more prominent role to ensure an adequate DOD response in this critical area.

  9. Quantum group spin nets: Refinement limit and relation to spin foams

    Science.gov (United States)

    Dittrich, Bianca; Martin-Benito, Mercedes; Steinhaus, Sebastian

    2014-07-01

    So far spin foam models are hardly understood beyond a few of their basic building blocks. To make progress on this question, we define analogue spin foam models, so-called "spin nets," for quantum groups SU(2)k and examine their effective continuum dynamics via tensor network renormalization. In the refinement limit of this coarse-graining procedure, we find a vast nontrivial fixed-point structure beyond the degenerate and the BF phase. In comparison to previous work, we use fixed-point intertwiners, inspired by Reisenberger's construction principle [M. P. Reisenberger, J. Math. Phys. (N.Y.) 40, 2046 (1999)] and the recent work [B. Dittrich and W. Kaminski, arXiv:1311.1798], as the initial parametrization. In this new parametrization fine-tuning is not required in order to flow to these new fixed points. Encouragingly, each fixed point has an associated extended phase, which allows for the study of phase transitions in the future. Finally we also present an interpretation of spin nets in terms of melonic spin foams. The coarse-graining flow of spin nets can thus be interpreted as describing the effective coupling between two spin foam vertices or space time atoms.

  10. Demand as frequency controlled reserve

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Z.; Togeby, M.; OEstergaard, J.

    2008-09-15

    Using demand as frequency controlled reserve (DFR) is an emerging technology which allow demand to participate actively in maintaining the system operation without reducing the energy service delivered to the customer and without need of user interaction. The basic premise is that traditional frequency controlled reserves from power plants and interconnections with neighbouring systems can be costly, slow and not fulfil the need for future power grids with a high share of wind power and fewer central power plants, and an intention to perform flexible operation such as is landing. Electricity demands, on the other hand, have advantages as frequency reserve including fast activation speed, smooth linear activation, low expected costs, and well-dispersed in the distribution grid. The main challenge of DFR is new methods for monitoring the available capacity. This project has investigated the technology of using electricity demands for providing frequency reserve to power systems. Within the project the potential and economy of DFR compatible loads in Denmark has been investigated, control logic has been designed, power system impact has been investigated, potential business models has been evaluated and an implementation strategy has been suggested. The tasks and goals of the project have been successfully accomplished based on which the conclusion and future recommendation are made. This project has developed the DFR technology that enables electricity demands to autonomously disconnect or reconnect to the grid in response to system frequency variations. The developed DFR technology is proved to be a promising technology from several perspectives. Technically, using DFR is feasible to provide reserves and enhance power system frequency control, while fulfilling technical requirements such as linear activation (or reconnection) according to frequency (or time). Environmentally, the DFR technology is pollution free in contrast to traditional reserves from generation

  11. Handbook on loss reserving

    CERN Document Server

    Schmidt, Klaus; Schnaus, Anja

    2016-01-01

    This handbook presents the basic aspects of actuarial loss reserving. Besides the traditional methods, it also includes a description of more recent ones and a discussion of certain problems occurring in actuarial practice, like inflation, scarce data, large claims, slow loss development, the use of market statistics, the need for simulation techniques and the task of calculating best estimates and ranges of future losses. In property and casualty insurance the provisions for payment obligations from losses that have occurred but have not yet been settled usually constitute the largest item on the liabilities side of an insurer's balance sheet. For this reason, the determination and evaluation of these loss reserves is of considerable economic importance for every property and casualty insurer. Actuarial students, academics as well as practicing actuaries will benefit from this overview of the most important actuarial methods of loss reserving by developing an understanding of the underlying stochastic models...

  12. Mesoscopic spin Hall effect in semiconductor nanostructures

    Science.gov (United States)

    Zarbo, Liviu

    The spin Hall effect (SHE) is a name given to a collection of diverse phenomena which share two principal features: (i) longitudinal electric current flowing through a paramagnetic semiconductor or metallic sample leads to transverse spin current and spin accumulation of opposite sign at opposing lateral edges; (ii) SHE does not require externally applied magnetic field or magnetic ordering in the equilibrium state of the sample, instead it relies on the presence of spin-orbit (SO) couplings within the sample. This thesis elaborates on a new type of phenomenon within the SHE family, predicted in our recent studies [Phys. Rev. B 72, 075361 (2005); Phys. Rev. Lett. 95, 046601 (2005); Phys. Rev. B 72, 075335 (2005); Phys. Rev. B 73 , 075303 (2006); and Europhys. Lett. 77, 47004 (2007)], where pure spin current flows through the transverse electrodes attached to a clean finitesize two-dimensional electron gas (2DEG) due to unpolarized charge current injected through its longitudinal leads. If transverse leads are removed, the effect manifests as nonequilibrium spin Hall accumulation at the lateral edges of 2DEG wires. The SO coupling driving this SHE effect is of the Rashba type, which arises due to structural inversion asymmetry of semiconductor heterostructure hosting the 2DEG. We term the effect "mesoscopic" because the spin Hall currents and accumulations reach optimal value in samples of the size of the spin precession length---the distance over which the spin of an electron precesses by an angle pi. In strongly SO-coupled structures this scale is of the order of ˜100 nm, and, therefore, mesoscopic in the sense of being much larger than the characteristic microscopic scales (such as the Fermi wavelength, screening length, or the mean free path in disordered systems), but still much smaller than the macroscopic ones. Although the first theoretical proposal for SHE, driven by asymmetry in SO-dependent scattering of spin-up and spin-down electrons off impurities

  13. Theory of spin Hall effect

    OpenAIRE

    Chudnovsky, Eugene M.

    2007-01-01

    An extension of Drude model is proposed that accounts for spin and spin-orbit interaction of charge carriers. Spin currents appear due to combined action of the external electric field, crystal field and scattering of charge carriers. The expression for spin Hall conductivity is derived for metals and semiconductors that is independent of the scattering mechanism. In cubic metals, spin Hall conductivity $\\sigma_s$ and charge conductivity $\\sigma_c$ are related through $\\sigma_s = [2 \\pi \\hbar...

  14. Brazilian uranium reserves

    International Nuclear Information System (INIS)

    Marques, J.P.M.

    1981-01-01

    Due to a growing demand of electric power to support Brasil's development, the use of nuclear energy will be indispensable. The nuclear fuel cycle for the production of energy, starts with the uranium exploration. The work performed in this field led to the discovery of several deposits in the country, which to-date totalize a reserve of 236,300t of U 308 , ranking Brazil in the 6th place among the nations of the western world holding uranium reserves. (Author) [pt

  15. SD-CAS: Spin Dynamics by Computer Algebra System.

    Science.gov (United States)

    Filip, Xenia; Filip, Claudiu

    2010-11-01

    A computer algebra tool for describing the Liouville-space quantum evolution of nuclear 1/2-spins is introduced and implemented within a computational framework named Spin Dynamics by Computer Algebra System (SD-CAS). A distinctive feature compared with numerical and previous computer algebra approaches to solving spin dynamics problems results from the fact that no matrix representation for spin operators is used in SD-CAS, which determines a full symbolic character to the performed computations. Spin correlations are stored in SD-CAS as four-entry nested lists of which size increases linearly with the number of spins into the system and are easily mapped into analytical expressions in terms of spin operator products. For the so defined SD-CAS spin correlations a set of specialized functions and procedures is introduced that are essential for implementing basic spin algebra operations, such as the spin operator products, commutators, and scalar products. They provide results in an abstract algebraic form: specific procedures to quantitatively evaluate such symbolic expressions with respect to the involved spin interaction parameters and experimental conditions are also discussed. Although the main focus in the present work is on laying the foundation for spin dynamics symbolic computation in NMR based on a non-matrix formalism, practical aspects are also considered throughout the theoretical development process. In particular, specific SD-CAS routines have been implemented using the YACAS computer algebra package (http://yacas.sourceforge.net), and their functionality was demonstrated on a few illustrative examples. Copyright © 2010 Elsevier Inc. All rights reserved.

  16. Spin-current emission governed by nonlinear spin dynamics.

    Science.gov (United States)

    Tashiro, Takaharu; Matsuura, Saki; Nomura, Akiyo; Watanabe, Shun; Kang, Keehoon; Sirringhaus, Henning; Ando, Kazuya

    2015-10-16

    Coupling between conduction electrons and localized magnetization is responsible for a variety of phenomena in spintronic devices. This coupling enables to generate spin currents from dynamical magnetization. Due to the nonlinearity of magnetization dynamics, the spin-current emission through the dynamical spin-exchange coupling offers a route for nonlinear generation of spin currents. Here, we demonstrate spin-current emission governed by nonlinear magnetization dynamics in a metal/magnetic insulator bilayer. The spin-current emission from the magnetic insulator is probed by the inverse spin Hall effect, which demonstrates nontrivial temperature and excitation power dependences of the voltage generation. The experimental results reveal that nonlinear magnetization dynamics and enhanced spin-current emission due to magnon scatterings are triggered by decreasing temperature. This result illustrates the crucial role of the nonlinear magnon interactions in the spin-current emission driven by dynamical magnetization, or nonequilibrium magnons, from magnetic insulators.

  17. Session 7: Reserve

    International Nuclear Information System (INIS)

    Bailey, R.; Crockford, G.

    2001-01-01

    The reserve session was devoted to some issues that came up through the workshop, which were grouped into three main areas: The Global Accelerator Network, Problems of stress and how to get organized to minimize them, What should an operations group be responsible for? This paper summarizes the discussions that took place. (author)

  18. SUIKERBOSRAND NATURE RESERVE

    African Journals Online (AJOL)

    reserve, the total length being 66 km with six overnight huts. There are also the BokmakiePie. Nature Troil. and the Cheetah Interpretive Troil. which can be used by day visitors. The former has two loops, one of 10 km and another of 17 km. The. Cheetah Troil. is much shorter and various points of interest are interpreted en ...

  19. School Shootings Stun Reservation

    Science.gov (United States)

    Borja, Rhea R.; Cavanagh, Sean

    2005-01-01

    This article deals with the impact brought by the school shootings at Red Lake Indian Reservation in Minnesota to the school community. A deeply troubled 16-year-old student shot and killed seven other people and himself at a high school. The nation's deadliest school attack since the 1999 slayings at Colorado's suburban Columbine High School took…

  20. Uranium reserves fall: AAEC

    International Nuclear Information System (INIS)

    Anon.

    1982-01-01

    Figures released by the AAEC show that Australia's reasonably assured resources of uranium recoverable at US$80 a kg fell by 5,000 tonnes during 1980-81. Reserves at 30 June 1981 totalled 294,000 tonnes. This represented 17 per cent of the Western World's low cost reasonably assured resources

  1. Electron spin dynamics and optical orientation of Mn2+ ions in GaAs

    Science.gov (United States)

    Akimov, I. A.; Dzhioev, R. I.; Korenev, V. L.; Kusrayev, Yu. G.; Sapega, V. F.; Yakovlev, D. R.; Bayer, M.

    2013-04-01

    We present an overview of spin-related phenomena in GaAs doped with low concentration of Mn-acceptors (below 1018 cm-3). We use the combination of different experimental techniques such as spin-flip Raman scattering and time-resolved photoluminescence. This allows to evaluate the time evolution of both electron and Mn spins. We show that optical orientation of Mn ions is possible under application of weak magnetic field, which is required to suppress the manganese spin relaxation. The optically oriented Mn2+ ions maintain the spin and return part of the polarization back to the electron spin system providing a long-lived electron spin memory. This leads to a bunch of spectacular effects such as non-exponential electron spin decay and spin precession in the effective exchange fields.

  2. Spin Torques in Systems with Spin Filtering and Spin Orbit Interaction

    KAUST Repository

    Ortiz Pauyac, Christian

    2016-06-19

    In the present thesis we introduce the reader to the field of spintronics and explore new phenomena, such as spin transfer torques, spin filtering, and three types of spin-orbit torques, Rashba, spin Hall, and spin swapping, which have emerged very recently and are promising candidates for a new generation of memory devices in computer technology. A general overview of these phenomena is presented in Chap. 1. In Chap. 2 we study spin transfer torques in tunnel junctions in the presence of spin filtering. In Chap. 3 we discuss the Rashba torque in ferromagnetic films, and in Chap. 4 we study spin Hall effect and spin swapping in ferromagnetic films, exploring the nature of spin-orbit torques based on these mechanisms. Conclusions and perspectives are summarized in Chap. 5.

  3. Electrically tunable spin polarization in silicene: A multi-terminal spin density matrix approach

    International Nuclear Information System (INIS)

    Chen, Son-Hsien

    2016-01-01

    Recent realized silicene field-effect transistor yields promising electronic applications. Using a multi-terminal spin density matrix approach, this paper presents an analysis of the spin polarizations in a silicene structure of the spin field-effect transistor by considering the intertwined intrinsic and Rashba spin–orbit couplings, gate voltage, Zeeman splitting, as well as disorder. Coexistence of the stagger potential and intrinsic spin–orbit coupling results in spin precession, making any in-plane polarization directions reachable by the gate voltage; specifically, the intrinsic coupling allows one to electrically adjust the in-plane components of the polarizations, while the Rashba coupling to adjust the out-of-plan polarizations. Larger electrically tunable ranges of in-plan polarizations are found in oppositely gated silicene than in the uniformly gated silicene. Polarizations in different phases behave distinguishably in weak disorder regime, while independent of the phases, stronger disorder leads to a saturation value. - Highlights: • Density matrix with spin rotations enables multi-terminal arbitrary spin injections. • Gate-voltage tunable in-plane polarizations require intrinsic SO coupling. • Gate-voltage tunable out-of-plane polarizations require Rashba SO coupling. • Oppositely gated silicene yields a large tunable range of in-plan polarizations. • Polarizations in different phases behave distinguishably only in weak disorder.

  4. Power generation scheduling. A free market based procedure with reserve constraints included

    International Nuclear Information System (INIS)

    Huse, Einar Staale

    1998-01-01

    This thesis deals with the short-term scheduling of electric power generation in a competitive market. This involves determination of start-ups and shut-downs, and production levels of all units in all hours of the optimization period, considering unit characteristics and system restrictions. The unit characteristics and restrictions handled are minimum and maximum production levels, fuel cost function, start-up costs, minimum up time and minimum down time. The system restrictions handled are power balance (supply equals demand in all hours) and spinning reserve requirement. The thesis has two main contributions: (1) A new organization of an hourly electric power market that simultaneously sets the price of both energy and reserve power is proposed. A power exchange is used as a trading place for electricity. Its responsibility is to balance supply and demand bids and to secure enough spinning reserve. Routines for bidding and market clearing are developed. (2) A computer programme that simulates the proposed electricity market has been implemented. The program can also be used as a new method for solving the single owner generation scheduling problem. Simulations show that the performance of the program is excellent. Simulations also show that it is possible to obtain efficient schedules through the proposed electricity market. 37 refs., 20 figs., 15 tabs

  5. Multi-objective market clearing of joint energy and reserves auctions ensuring power system security

    International Nuclear Information System (INIS)

    Aghaei, J.; Shayanfar, H.; Amjady, N.

    2009-01-01

    A model and solution approach to day-ahead market clearing of joint energy and reserves auctions is proposed in this paper. The model represents the clearing system used by ISO in charge of both the market operation and system security. A Multiobjective Mathematical Programming (MMP) formulation is implemented for provision of ancillary services (Automatic Generation Control or AGC, Spinning, Non-spinning and operational reserves) as well as energy in simultaneous auctions by pool-based aggregated market scheme. System security is taken into account in the market clearing procedure as the extra objective functions of the optimization problem. So, in the MMP formulation of the market clearing process, the objective functions (generation cost and security indices) are optimized while meeting AC power flow constraints, system reserve requirements and lost opportunity cost (LOC) considerations. The model is applied to the IEEE 24-bus Reliability Test System (IEEE 24-bus RTS), and simulation studies are carried out to examine the effectiveness of the proposed method

  6. Power generation scheduling. A free market based procedure with reserve constraints included

    Energy Technology Data Exchange (ETDEWEB)

    Huse, Einar Staale

    1999-12-31

    This thesis deals with the short-term scheduling of electric power generation in a competitive market. This involves determination of start-ups and shut-downs, and production levels of all units in all hours of the optimization period, considering unit characteristics and system restrictions. The unit characteristics and restrictions handled are minimum and maximum production levels, fuel cost function, start-up costs, minimum up time and minimum down time. The system restrictions handled are power balance (supply equals demand in all hours) and spinning reserve requirement. The thesis has two main contributions: (1) A new organization of an hourly electric power market that simultaneously sets the price of both energy and reserve power is proposed. A power exchange is used as a trading place for electricity. Its responsibility is to balance supply and demand bids and to secure enough spinning reserve. Routines for bidding and market clearing are developed. (2) A computer programme that simulates the proposed electricity market has been implemented. The program can also be used as a new method for solving the single owner generation scheduling problem. Simulations show that the performance of the program is excellent. Simulations also show that it is possible to obtain efficient schedules through the proposed electricity market. 37 refs., 20 figs., 15 tabs.

  7. Power generation scheduling. A free market based procedure with reserve constraints included

    Energy Technology Data Exchange (ETDEWEB)

    Huse, Einar Staale

    1998-12-31

    This thesis deals with the short-term scheduling of electric power generation in a competitive market. This involves determination of start-ups and shut-downs, and production levels of all units in all hours of the optimization period, considering unit characteristics and system restrictions. The unit characteristics and restrictions handled are minimum and maximum production levels, fuel cost function, start-up costs, minimum up time and minimum down time. The system restrictions handled are power balance (supply equals demand in all hours) and spinning reserve requirement. The thesis has two main contributions: (1) A new organization of an hourly electric power market that simultaneously sets the price of both energy and reserve power is proposed. A power exchange is used as a trading place for electricity. Its responsibility is to balance supply and demand bids and to secure enough spinning reserve. Routines for bidding and market clearing are developed. (2) A computer programme that simulates the proposed electricity market has been implemented. The program can also be used as a new method for solving the single owner generation scheduling problem. Simulations show that the performance of the program is excellent. Simulations also show that it is possible to obtain efficient schedules through the proposed electricity market. 37 refs., 20 figs., 15 tabs.

  8. BROOKHAVEN: Spin rotator to boost polarization

    International Nuclear Information System (INIS)

    Anon.

    1991-01-01

    The Alternating Gradient Synchrotron (AGS) at Brookhaven holds the world record energy for spin polarized proton beams at 22 GeV. However this required a complicated two-week commissioning effort to overcome 39 imperfection depolarizing resonances and six intrinsic depolarizing resonances

  9. Optical spin generation/detection and spin transport lifetimes

    International Nuclear Information System (INIS)

    Miah, M. Idrish

    2011-01-01

    We generate electron spins in semiconductors by optical pumping. The detection of them is also performed by optical technique using time-resolved pump-probe photoluminescence polarization measurements in the presence of an external magnetic field perpendicular to the generated spin. The spin polarization in dependences of the pulse length, pump-probe delay and external magnetic field is studied. From the dependence of spin-polarization on the delay of the probe, the electronic spin transport lifetimes and the spin relaxation frequencies as a function of the strength of the magnetic field are estimated. The results are discussed based on hyperfine effects for interacting electrons.

  10. Optical spin generation/detection and spin transport lifetimes

    Energy Technology Data Exchange (ETDEWEB)

    Miah, M. Idrish, E-mail: m.miah@griffith.edu.au [Department of Physics, University of Chittagong, Chittagong 4331 (Bangladesh)

    2011-02-25

    We generate electron spins in semiconductors by optical pumping. The detection of them is also performed by optical technique using time-resolved pump-probe photoluminescence polarization measurements in the presence of an external magnetic field perpendicular to the generated spin. The spin polarization in dependences of the pulse length, pump-probe delay and external magnetic field is studied. From the dependence of spin-polarization on the delay of the probe, the electronic spin transport lifetimes and the spin relaxation frequencies as a function of the strength of the magnetic field are estimated. The results are discussed based on hyperfine effects for interacting electrons.

  11. Magnetocaloric effect in quantum spin-s chains

    Directory of Open Access Journals (Sweden)

    A. Honecker

    2009-01-01

    Full Text Available We compute the entropy of antiferromagnetic quantum spin-s chains in an external magnetic field using exact diagonalization and Quantum Monte Carlo simulations. The magnetocaloric effect, i. e., temperature variations during adiabatic field changes, can be derived from the isentropes. First, we focus on the example of the spin-s=1 chain and show that one can cool by closing the Haldane gap with a magnetic field. We then move to quantum spin-s chains and demonstrate linear scaling with s close to the saturation field. In passing, we propose a new method to compute many low-lying excited states using the Lanczos recursion.

  12. Rotational Invariance of the 2d Spin - Spin Correlation Function

    Science.gov (United States)

    Pinson, Haru

    2012-09-01

    At the critical temperature in the 2d Ising model on the square lattice, we establish the rotational invariance of the spin-spin correlation function using the asymptotics of the spin-spin correlation function along special directions (McCoy and Wu in the two dimensional Ising model. Harvard University Press, Cambridge, 1973) and the finite difference Hirota equation for which the spin-spin correlation function is shown to satisfy (Perk in Phys Lett A 79:3-5, 1980; Perk in Proceedings of III international symposium on selected topics in statistical mechanics, Dubna, August 22-26, 1984, JINR, vol II, pp 138-151, 1985).

  13. 26 CFR 1.801-5 - Total reserves.

    Science.gov (United States)

    2010-04-01

    ... TAXES Life Insurance Companies § 1.801-5 Total reserves. (a) Total reserves defined. For purposes of... its highest aggregate reserve by taking State A's requirement of 10 against its life insurance business and adding it to State B's requirement of 7 against its annuity business. (b) Reserves required by...

  14. 24 CFR 904.111 - Nonroutine Maintenance Reserve (NRMR).

    Science.gov (United States)

    2010-04-01

    ... the annual reserve requirement, and (3) show the total reserve requirements for all the listed items... reserve requirements for 90 days the LHA shall invest the excess in federally insured savings accounts... 24 Housing and Urban Development 4 2010-04-01 2010-04-01 false Nonroutine Maintenance Reserve...

  15. A CAMAC-resident microprocessor for the monitoring of polarimeter spin states

    International Nuclear Information System (INIS)

    Reid, D.; DuPlantis, D.; Yoder, N.; Dale, D.

    1992-01-01

    A CAMAC module for the reporting of polarimeter spin states is being developed using a resident microcontroller. The module will allow experimenters at the Indiana University Cyclotron Facility to monitor spin states and correlate spin information with other experimental data. The use of a microprocessor allows for adaptation of the module as new requirements ensue without change to the printed circuit board layout. (author)

  16. Effects of Confinement on Conventional Spin Problems

    DEFF Research Database (Denmark)

    Marchukov, Oleksandr

    2015-01-01

    In recent years quantum simulations in cold-atom set-ups has attracted a lot of interest both from experimental and theoretical research groups around the world. Unprecedented level of control over physical systems allowed one to investigate rather peculiar models, such as artificial gauge fields...... to the quantum signa- tures of chaos are discussed. The second part of the dissertation is concerned with quantum state transfer in one-dimensional spin chains. The properties required to achieve conditional state transfer, i.e. “allowing” or “blocking” of state transfer depending on the parameters of the spin...... chain, are discussed....

  17. Spin-polarized fuel in ICF pellets

    International Nuclear Information System (INIS)

    Wakuta, Yoshihisa; Emoto, Nobuya; Nakao, Yasuyuki; Honda, Takuro; Honda, Yoshinori; Nakashima, Hideki.

    1990-01-01

    The use of parallel spin-polarized DT or D 3 He fuel increases the fusion cross-section by 50%. By implosion-burn simulation for inertially confined fusion (ICF) pellets of the spin-polarized fuels, we found that the input energy requirement could be reduced by nearly a fact of two. These pellets taken up here include large-high-aspect-ratio DT target proposed in ILE Osaka University and DT ignitor/D 3 He fuel pellet proposed by our group. We also found that the polarized state could survive during the implosion-burn phase. (author)

  18. Spin-zero mesons and current algebras

    International Nuclear Information System (INIS)

    Wellner, M.

    1977-01-01

    Large chiral algebras, using the f and d coefficients of SU(3) can be constructed with spin-1/2 baryons. Such algebras have been found useful in some previous investigations. This article examines under what conditions similar or identical current algebras may be realized with spin-0 mesons. A curious lack of analogy emerges between meson and baryon currents. Second-class currents, made of mesons, are required in some algebras. If meson and baryon currents are to satisfy the same extended SU(3) algebra, four meson nonets are needed, in terms of which we give an explicit construction for the currents

  19. Overview of spin physics

    International Nuclear Information System (INIS)

    Yokosawa, A.

    1992-01-01

    Spin physics activities at medium and high energies became significantly active when polarized targets and polarized beams became accessible for hadron-hadron scattering experiments. My overview of spin physics will be inclined to the study of strong interaction using facilities at Argonne ZGS, Brookhaven AGS (including RHIC), CERN, Fermilab, LAMPF, an SATURNE. In 1960 accelerator physicists had already been convinced that the ZGS could be unique in accelerating a polarized beam; polarized beams were being accelerated through linear accelerators elsewhere at that time. However, there was much concern about going ahead with the construction of a polarized beam because (i) the source intensity was not high enough to accelerate in the accelerator, (ii) the use of the accelerator would be limited to only polarized-beam physics, that is, proton-proton interaction, and (iii) p-p elastic scattering was not the most popular topic in high-energy physics. In fact, within spin physics, π-nucleon physics looked attractive, since the determination of spin and parity of possible πp resonances attracted much attention. To proceed we needed more data beside total cross sections and elastic differential cross sections; measurements of polarization and other parameters were urgently needed. Polarization measurements had traditionally been performed by analyzing the spin of recoil protons. The drawbacks of this technique are: (i) it involves double scattering, resulting in poor accuracy of the data, and (ii) a carbon analyzer can only be used for a limited region of energy

  20. Noise in tunneling spin current across coupled quantum spin chains

    Science.gov (United States)

    Aftergood, Joshua; Takei, So

    2018-01-01

    We theoretically study the spin current and its dc noise generated between two spin-1 /2 spin chains weakly coupled at a single site in the presence of an over-population of spin excitations and a temperature elevation in one subsystem relative to the other, and we compare the corresponding transport quantities across two weakly coupled magnetic insulators hosting magnons. In the spin chain scenario, we find that applying a temperature bias exclusively leads to a vanishing spin current and a concomitant divergence in the spin Fano factor, defined as the spin current noise-to-signal ratio. This divergence is shown to have an exact analogy to the physics of electron scattering between fractional quantum Hall edge states and not to arise in the magnon scenario. We also reveal a suppression in the spin current noise that exclusively arises in the spin chain scenario due to the fermion nature of the spin-1/2 operators. We discuss how the spin Fano factor may be extracted experimentally via the inverse spin Hall effect used extensively in spintronics.

  1. Storing quantum information in spins and high-sensitivity ESR.

    Science.gov (United States)

    Morton, John J L; Bertet, Patrice

    2018-02-01

    Quantum information, encoded within the states of quantum systems, represents a novel and rich form of information which has inspired new types of computers and communications systems. Many diverse electron spin systems have been studied with a view to storing quantum information, including molecular radicals, point defects and impurities in inorganic systems, and quantum dots in semiconductor devices. In these systems, spin coherence times can exceed seconds, single spins can be addressed through electrical and optical methods, and new spin systems with advantageous properties continue to be identified. Spin ensembles strongly coupled to microwave resonators can, in principle, be used to store the coherent states of single microwave photons, enabling so-called microwave quantum memories. We discuss key requirements in realising such memories, including considerations for superconducting resonators whose frequency can be tuned onto resonance with the spins. Finally, progress towards microwave quantum memories and other developments in the field of superconducting quantum devices are being used to push the limits of sensitivity of inductively-detected electron spin resonance. The state-of-the-art currently stands at around 65 spins per Hz, with prospects to scale down to even fewer spins. Copyright © 2017. Published by Elsevier Inc.

  2. Storing quantum information in spins and high-sensitivity ESR

    Science.gov (United States)

    Morton, John J. L.; Bertet, Patrice

    2018-02-01

    Quantum information, encoded within the states of quantum systems, represents a novel and rich form of information which has inspired new types of computers and communications systems. Many diverse electron spin systems have been studied with a view to storing quantum information, including molecular radicals, point defects and impurities in inorganic systems, and quantum dots in semiconductor devices. In these systems, spin coherence times can exceed seconds, single spins can be addressed through electrical and optical methods, and new spin systems with advantageous properties continue to be identified. Spin ensembles strongly coupled to microwave resonators can, in principle, be used to store the coherent states of single microwave photons, enabling so-called microwave quantum memories. We discuss key requirements in realising such memories, including considerations for superconducting resonators whose frequency can be tuned onto resonance with the spins. Finally, progress towards microwave quantum memories and other developments in the field of superconducting quantum devices are being used to push the limits of sensitivity of inductively-detected electron spin resonance. The state-of-the-art currently stands at around 65 spins per √{ Hz } , with prospects to scale down to even fewer spins.

  3. Electrical control of single hole spins in nanowire quantum dots.

    Science.gov (United States)

    Pribiag, V S; Nadj-Perge, S; Frolov, S M; van den Berg, J W G; van Weperen, I; Plissard, S R; Bakkers, E P A M; Kouwenhoven, L P

    2013-03-01

    The development of viable quantum computation devices will require the ability to preserve the coherence of quantum bits (qubits). Single electron spins in semiconductor quantum dots are a versatile platform for quantum information processing, but controlling decoherence remains a considerable challenge. Hole spins in III-V semiconductors have unique properties, such as a strong spin-orbit interaction and weak coupling to nuclear spins, and therefore, have the potential for enhanced spin control and longer coherence times. A weaker hyperfine interaction has previously been reported in self-assembled quantum dots using quantum optics techniques, but the development of hole-spin-based electronic devices in conventional III-V heterostructures has been limited by fabrication challenges. Here, we show that gate-tunable hole quantum dots can be formed in InSb nanowires and used to demonstrate Pauli spin blockade and electrical control of single hole spins. The devices are fully tunable between hole and electron quantum dots, which allows the hyperfine interaction strengths, g-factors and spin blockade anisotropies to be compared directly in the two regimes.

  4. Generalized Momentum Control of the Spin-Stabilized Magnetospheric Multiscale (MMS) Formation

    Science.gov (United States)

    Benegalrao, Suyog; Queen, Steven; Shah, Neerav; Blackman, Kathleen

    2015-01-01

    Angular momentum control maneuvers required to keep spin-axis in science box. Traditional approach uses de-coupled modes for pointing, spin, nutation Impractical for MMS Frequency and Number of maneuvers (Orbit Control, Pointing, Nutation, Spin, four observatories, every 2-4 weeks). Difficult to implement de-coupled open-loop control with flexible wire booms. Desire a unified angular momentum controller. Comprehensively control pointing, spin, and nutation.

  5. Spin Structures in Magnetic Nanoparticles

    DEFF Research Database (Denmark)

    Mørup, Steen; Brok, Erik; Frandsen, Cathrine

    2013-01-01

    Spin structures in nanoparticles of ferrimagnetic materials may deviate locally in a nontrivial way from ideal collinear spin structures. For instance, magnetic frustration due to the reduced numbers of magnetic neighbors at the particle surface or around defects in the interior can lead to spin...... canting and hence a reduced magnetization. Moreover, relaxation between almost degenerate canted spin states can lead to anomalous temperature dependences of the magnetization at low temperatures. In ensembles of nanoparticles, interparticle exchange interactions can also result in spin reorientation....... Here, we give a short review of anomalous spin structures in nanoparticles....

  6. Spinning-disk confocal microscopy: present technology and future trends.

    Science.gov (United States)

    Oreopoulos, John; Berman, Richard; Browne, Mark

    2014-01-01

    Live-cell imaging requires not only high temporal resolution but also illumination powers low enough to minimize photodamage. Traditional single-point laser scanning confocal microscopy (LSCM) is generally limited by both the relatively slow speed at which it can acquire optical sections by serial raster scanning (a few Hz) and the higher potential for phototoxicity. These limitations have driven the development of rapid, parallel forms of confocal microscopy, the most popular of which is the spinning-disk confocal microscope (SDCM). Here, we briefly introduce the SDCM technique, discuss its strengths and weaknesses against LSCM, and update the reader on some recent developments in SDCM technology that improve its performance and expand its utility for life science research now and in the future. © 2014 Elsevier Inc. All rights reserved.

  7. Spin-Driven Emergent Antiferromagnetism and Metal-Insulator Transition in Nanoscale p-Si

    Science.gov (United States)

    Lou, Paul C.; Kumar, Sandeep

    2018-04-01

    The entanglement of the charge, spin and orbital degrees of freedom can give rise to emergent behavior especially in thin films, surfaces and interfaces. Often, materials that exhibit those properties require large spin orbit coupling. We hypothesize that the emergent behavior can also occur due to spin, electron and phonon interactions in widely studied simple materials such as Si. That is, large intrinsic spin-orbit coupling is not an essential requirement for emergent behavior. The central hypothesis is that when one of the specimen dimensions is of the same order (or smaller) as the spin diffusion length, then non-equilibrium spin accumulation due to spin injection or spin-Hall effect (SHE) will lead to emergent phase transformations in the non-ferromagnetic semiconductors. In this experimental work, we report spin mediated emergent antiferromagnetism and metal insulator transition in a Pd (1 nm)/Ni81Fe19 (25 nm)/MgO (1 nm)/p-Si (~400 nm) thin film specimen. The spin-Hall effect in p-Si, observed through Rashba spin-orbit coupling mediated spin-Hall magnetoresistance behavior, is proposed to cause the spin accumulation and resulting emergent behavior. The phase transition is discovered from the diverging behavior in longitudinal third harmonic voltage, which is related to the thermal conductivity and heat capacity.

  8. Spin entanglement, decoherence and Bohm's EPR paradox.

    Science.gov (United States)

    Cavalcanti, E G; Drummond, P D; Bachor, H A; Reid, M D

    2009-10-12

    We obtain criteria for entanglement and the EPR paradox for spin-entangled particles and analyse the effects of decoherence caused by absorption and state purity errors. For a two qubit photonic state, entanglement can occur for all transmission efficiencies. In this case, the state preparation purity must be above a threshold value. However, Bohm's spin EPR paradox can be achieved only above a critical level of loss. We calculate a required efficiency of 58%, which appears achievable with current quantum optical technologies. For a macroscopic number of particles prepared in a correlated state, spin entanglement and the EPR paradox can be demonstrated using our criteria for efficiencies eta > 1/3 and eta > 2/3 respectively. This indicates a surprising insensitivity to loss decoherence, in a macroscopic system of ultra-cold atoms or photons.

  9. Spin-3/2 Pentaquark Resonance Signature

    International Nuclear Information System (INIS)

    Ben Lasscock; John Hedditch; Derek Leinweber; Anthony Williams; Waseem Kamleh; Wolodymyr Melnitchouk; Anthony Thomas; Ross Young; James Zanotti

    2005-01-01

    We search for the standard lattice resonance signature of attraction between the resonance constituents which leads to a bound state at quark masses near the physical regime. We study a variety of spin-1/2 interpolators and for the first time, interpolators providing access to spin-3/2 pentaquark states. In looking for evidence of binding, a precise determination of the mass splitting between the pentaquark state and its lowest-lying decay channel is performed by constructing the effective mass splitting from the various two-point correlation functions. While the binding of the pentaquark state is not a requirement, the observation of such binding would provide compelling evidence for the existence of the theta+ pentaquark resonance. Evidence of binding is observed in the isoscalar spin-3/2 positive parity channel, making it an interesting state for further research

  10. Wiggler as spin rotators for RHIC

    International Nuclear Information System (INIS)

    Luccio, A.; Conte, M.

    1993-01-01

    The spin of a polarized particle in a circular accelerator can be rotated with an arrangement of dipoles with field mutually perpendicular and perpendicular to the orbit. To achieve spin rotation, a given field integral value is required. The device must be designed in a way that the particle orbit is distorted as little as possible. It is shown that wigglers with many periods are suitable to achieve spin rotation with minimum orbit distortions. Wigglers are also more compact than more established structures and will use less electric power. Additional advantages include their use for non distructive beam diagnostics. Results are given for the Relativistic Heavy Ion Collider (RHIC) in the polarized proton mode

  11. Long coherence times for edge spins

    Science.gov (United States)

    Kemp, Jack; Yao, Norman Y.; Laumann, Christopher R.; Fendley, Paul

    2017-06-01

    We show that in certain one-dimensional spin chains with open boundary conditions, the edge spins retain memory of their initial state for very long times, even at infinite temperature. The long coherence times do not require disorder, only an ordered phase. In the integrable Ising and XYZ chains, the presence of a strong zero mode means the coherence time is infinite. When Ising is perturbed by interactions breaking the integrability, the coherence time remains exponentially long in the perturbing couplings. We show that this is a consequence of an edge ‘almost’ strong zero mode that almost commutes with the Hamiltonian. We compute this operator explicitly, allowing us to estimate accurately the plateau value of edge spin autocorrelator.

  12. SPIN-selling

    CERN Document Server

    Rackham, Neil

    1995-01-01

    True or false? In selling high-value products or services: "closing" increases your chance of success; it is essential to describe the benefits of your product or service to the customer; objection handling is an important skill; and open questions are more effective than closed questions. All false, says Neil Rackham. He and his team studied more than 35,000 sales calls made by 10,000 sales people in 23 countries over 12 years. Their findings revealed that many of the methods developed for selling low-value goods just don't work for major sales. Rackham went on to introduce his SPIN-selling method, where SPIN describes the whole selling process - Situation questions, Problem questions, Implication questions, Need-payoff questions. SPIN-selling provides you with a set of simple and practical techniques which have been tried in many of today's leading companies with dramatic improvements to their sales performance.

  13. Perspectives on spin glasses

    CERN Document Server

    Contucci, Pierluigi

    2013-01-01

    Presenting and developing the theory of spin glasses as a prototype for complex systems, this book is a rigorous and up-to-date introduction to their properties. The book combines a mathematical description with a physical insight of spin glass models. Topics covered include the physical origins of those models and their treatment with replica theory; mathematical properties like correlation inequalities and their use in the thermodynamic limit theory; main exact solutions of the mean field models and their probabilistic structures; and the theory of the structural properties of the spin glass phase such as stochastic stability and the overlap identities. Finally, a detailed account is given of the recent numerical simulation results and properties, including overlap equivalence, ultrametricity and decay of correlations. The book is ideal for mathematical physicists and probabilists working in disordered systems.

  14. Spin Waves in Terbium

    DEFF Research Database (Denmark)

    Jensen, J.; Houmann, Jens Christian Gylden

    1975-01-01

    The selection rules for the linear couplings between magnons and phonons propagating in the c direction of a simple basal-plane hcp ferromagnet are determined by general symmetry considerations. The acoustic-optical magnon-phonon interactions observed in the heavy-rare-earth metals have been...... explained by Liu as originating from the mixing of the spin states of the conduction electrons due to the spin-orbit coupling. We find that this coupling mechanism introduces interactions which violate the selection rules for a simple ferromagnet. The interactions between the magnons and phonons propagating...... in the c direction of Tb have been studied experimentally by means of inelastic neutron scattering. The magnons are coupled to both the acoustic- and optical-transverse phonons. By studying the behavior of the acoustic-optical coupling, we conclude that it is a spin-mixed-induced coupling as proposed...

  15. Microadaptive Flow Control Applied to a Spinning Projectile

    National Research Council Canada - National Science Library

    McMichael, J; Lovas, A; Plostins, P; Sahu, J; Brown, G; Glezer, A

    2005-01-01

    ... technology developed, the flight control technology required to enable the MAFC on spinning projectiles, the design of the flight test and validation hardware, and the results of the open-loop flight test...

  16. Homoepitaxial graphene tunnel barriers for spin transport

    Directory of Open Access Journals (Sweden)

    Adam L. Friedman

    2016-05-01

    Full Text Available Tunnel barriers are key elements for both charge-and spin-based electronics, offering devices with reduced power consumption and new paradigms for information processing. Such devices require mating dissimilar materials, raising issues of heteroepitaxy, interface stability, and electronic states that severely complicate fabrication and compromise performance. Graphene is the perfect tunnel barrier. It is an insulator out-of-plane, possesses a defect-free, linear habit, and is impervious to interdiffusion. Nonetheless, true tunneling between two stacked graphene layers is not possible in environmental conditions usable for electronics applications. However, two stacked graphene layers can be decoupled using chemical functionalization. Here, we demonstrate that hydrogenation or fluorination of graphene can be used to create a tunnel barrier. We demonstrate successful tunneling by measuring non-linear IV curves and a weakly temperature dependent zero-bias resistance. We demonstrate lateral transport of spin currents in non-local spin-valve structures, and determine spin lifetimes with the non-local Hanle effect. We compare the results for hydrogenated and fluorinated tunnel and we discuss the possibility that ferromagnetic moments in the hydrogenated graphene tunnel barrier affect the spin transport of our devices.

  17. Homoepitaxial graphene tunnel barriers for spin transport

    Science.gov (United States)

    Friedman, Adam L.; van't Erve, Olaf M. J.; Robinson, Jeremy T.; Whitener, Keith E.; Jonker, Berend T.

    2016-05-01

    Tunnel barriers are key elements for both charge-and spin-based electronics, offering devices with reduced power consumption and new paradigms for information processing. Such devices require mating dissimilar materials, raising issues of heteroepitaxy, interface stability, and electronic states that severely complicate fabrication and compromise performance. Graphene is the perfect tunnel barrier. It is an insulator out-of-plane, possesses a defect-free, linear habit, and is impervious to interdiffusion. Nonetheless, true tunneling between two stacked graphene layers is not possible in environmental conditions usable for electronics applications. However, two stacked graphene layers can be decoupled using chemical functionalization. Here, we demonstrate that hydrogenation or fluorination of graphene can be used to create a tunnel barrier. We demonstrate successful tunneling by measuring non-linear IV curves and a weakly temperature dependent zero-bias resistance. We demonstrate lateral transport of spin currents in non-local spin-valve structures, and determine spin lifetimes with the non-local Hanle effect. We compare the results for hydrogenated and fluorinated tunnel and we discuss the possibility that ferromagnetic moments in the hydrogenated graphene tunnel barrier affect the spin transport of our devices.

  18. Fractional Reserve Banking

    OpenAIRE

    Andreasen, Niels; Bjerregaard, Mads; Lund, Jonas; Olsen, Ove Bitsch; Rasmussen, Andreas Dalgas

    2012-01-01

    Projektet er bygget op omkring kritisk realisme, som er det gennemgående videnskabelige fundament til undersøgelsen af hvilke strukturelle grunde der er til finansiel ustabilitet i Danmark. Projektet går i dybden med Fractional Reserve Banking og incitamentsstrukturen i banksystemet. Vi bevæger os både på det makro- og mikroøkonomiske niveau i analysen. På makro niveau bruger vi den østrigske skole om konjunktur teori (The Positive Theory of the Cycle). På mikro niveau arbejder vi med princip...

  19. Spin Physics at COMPASS

    International Nuclear Information System (INIS)

    Schill, Christian

    2012-01-01

    The COMPASS experiment is a fixed target experiment at the CERN SPS using muon and hadron beams for the investigation of the spin structure of the nucleon and hadron spectroscopy. The main objective of the muon physics program is the study of the spin of the nucleon in terms of its constituents, quarks and gluons. COMPASS has accumulated data during 6 years scattering polarized muons off longitudinally or transversely polarized deuteron ( 6 LiD) or proton (NH 3 ) targets. Results for the gluon polarization are obtained from longitudinal double spin cross section asymmetries using two different channels, open charm production and high transverse momentum hadron pairs, both proceeding through the photon-gluon fusion process. Also, the longitudinal spin structure functions of the proton and the deuteron were measured in parallel as well as the helicity distributions for the three lightest quark flavours. With a transversely polarized target, results were obtained with proton and deuteron targets for the Collins and Sivers asymmetries for charged hadrons as well as for identified kaons and pions. The Collins asymmetry is sensitive to the transverse spin structure of the nucleon, while the Sivers asymmetry reflects correlations between the quark transverse momentum and the nucleon spin. Recently, a new proposal for the COMPASS II experiment was accepted by the CERN SPS which includes two new topics: Exclusive reactions like DVCS and DVMP using the muon beam and a hydrogen target to study generalized parton distributions and Drell-Yan measurements using a pion beam and a polarized NH 3 target to study transverse momentum dependent distributions.

  20. Control of electron spin decoherence in nuclear spin baths

    Science.gov (United States)

    Liu, Ren-Bao

    2011-03-01

    Nuclear spin baths are a main mechanism of decoherence of spin qubits in solid-state systems, such as quantum dots and nitrogen-vacancy (NV) centers of diamond. The decoherence results from entanglement between the electron and nuclear spins, established by quantum evolution of the bath conditioned on the electron spin state. When the electron spin is flipped, the conditional bath evolution is manipulated. Such manipulation of bath through control of the electron spin not only leads to preservation of the center spin coherence but also demonstrates quantum nature of the bath. In an NV center system, the electron spin effectively interacts with hundreds of 13 C nuclear spins. Under repeated flip control (dynamical decoupling), the electron spin coherence can be preserved for a long time (> 1 ms) . Thereforesomecharacteristicoscillations , duetocouplingtoabonded 13 C nuclear spin pair (a dimer), are imprinted on the electron spin coherence profile, which are very sensitive to the position and orientation of the dimer. With such finger-print oscillations, a dimer can be uniquely identified. Thus, we propose magnetometry with single-nucleus sensitivity and atomic resolution, using NV center spin coherence to identify single molecules. Through the center spin coherence, we could also explore the many-body physics in an interacting spin bath. The information of elementary excitations and many-body correlations can be extracted from the center spin coherence under many-pulse dynamical decoupling control. Another application of the preserved spin coherence is identifying quantumness of a spin bath through the back-action of the electron spin to the bath. We show that the multiple transition of an NV center in a nuclear spin bath can have longer coherence time than the single transition does, when the classical noises due to inhomogeneous broadening is removed by spin echo. This counter-intuitive result unambiguously demonstrates the quantumness of the nuclear spin bath

  1. Spin Physics at RHIC

    International Nuclear Information System (INIS)

    Bland, L.C.

    2003-01-01

    The physics goals that will be addressed by colliding polarized protons at the Relativistic Heavy Ion Collider (RHIC) are described. The RHIC spin program provides a new generation of experiments that will unfold the quark, anti-quark and gluon contributions to the proton's spin. In addition to these longer term goals, this paper describes what was learned from the first polarized proton collisions at √(s)=200 GeV. These collisions took place in a five-week run during the second year of RHIC operation

  2. CONFERENCE: Muon spin rotation

    Energy Technology Data Exchange (ETDEWEB)

    Karlsson, Erik

    1986-11-15

    An international physics conference centred on muons without a word about leptons, weak interactions, EMC effects, exotic decay modes or any other standard high energy physics jargon. Could such a thing even have been imagined ten years ago? Yet about 120 physicists and chemists from 16 nations gathered at the end of June in Uppsala (Sweden) for their fourth meeting on Muon Spin Rotation, Relaxation and Resonance, without worrying about the muon as an elementary particle. This reflects how the experimental techniques based on the muon spin interactions have reached maturity and are widely recognized by condensed matter physicists and specialized chemists as useful tools.

  3. Spin Waves in Terbium

    DEFF Research Database (Denmark)

    Jensen, J.; Houmann, Jens Christian Gylden; Bjerrum Møller, Hans

    1975-01-01

    with the symmetry, we deduce the dispersion relation for the spin waves in a basal-plane ferromagnet. This phenomenological spin-wave theory accounts for the observed behavior of the magnon energies in Tb. The two q⃗-dependent Bogoliubov components of the magnon energies are derived from the experimental results......, which are corrected for the effect of the direct coupling between the magnons and the phonons, and for the field dependence of the relative magnetization at finite temperatures. A large q⃗-dependent difference between the two energy components is observed, showing that the anisotropy of the two...

  4. Spin puzzle in nucleon

    International Nuclear Information System (INIS)

    Ramachandran, R.

    1994-09-01

    The object of this brief review is to reconcile different points of view on how the spin of proton is made up from its constituents. On the basis of naive quark model with flavour symmetry such as isospin or SU(3) one finds a static description. On the contrary the local SU(3) colour symmetry gives a dynamical view. Both these views are contrasted and the role of U(1) axial anomaly and the ambiguity for the measurable spin content is discussed. (author). 16 refs, 1 fig

  5. Naval Reserve Annual Operating Costs

    Science.gov (United States)

    1975-10-29

    C. c ) CPi i 0 0 00 0 le C C.C~r In 1]1 In 00 It .- I to C-38 ’U2 WIX ’W~ - m u. -C-LC m4 C v , v ul FA ?w % -D 1 o r cl jc j, II t %c oK W)i Ir of... platform programs, while Program 11 contains 26 sub-programs each having a separate Reserve program sponsor. The distribution of Program 11 resources is...a mix of specific skills required to bring an active Navy oper-Iating platform to organizational manning. Each SRU is tailored to a specific ship

  6. Spin-locking and cross-polarization under magic-angle spinning of uniformly labeled solids.

    Science.gov (United States)

    Hung, Ivan; Gan, Zhehong

    2015-07-01

    Spin-locking and cross-polarization under magic-angle spinning are investigated for uniformly (13)C and (15)N labeled solids. In particular, the interferences from chemical shift anisotropy, and (1)H heteronuclear and (13)C homonuclear dipolar couplings are identified. The physical origin of these interferences provides guidelines for selecting the best (13)C and (15)N polarization transfer rf fields. Optimal settings for both the zero- and double-quantum cross-polarization transfer mechanisms are recommended. Copyright © 2015 Elsevier Inc. All rights reserved.

  7. Spin transfer torque with spin diffusion in magnetic tunnel junctions

    KAUST Repository

    Manchon, Aurelien; Matsumoto, R.; Jaffres, H.; Grollier, J.

    2012-01-01

    in the metallic layers. We show that spin diffusion mixes the transverse spin current components and dramatically modifies the bias dependence of the effective spin transfer torque. This leads to a significant linear bias dependence of the out-of-plane torque

  8. K-band single-chip electron spin resonance detector.

    Science.gov (United States)

    Anders, Jens; Angerhofer, Alexander; Boero, Giovanni

    2012-04-01

    We report on the design, fabrication, and characterization of an integrated detector for electron spin resonance spectroscopy operating at 27 GHz. The microsystem, consisting of an LC-oscillator and a frequency division module, is integrated onto a single silicon chip using a conventional complementary metal-oxide-semiconductor technology. The achieved room temperature spin sensitivity is about 10(8)spins/G Hz(1/2), with a sensitive volume of about (100 μm)(3). Operation at 77K is also demonstrated. Copyright © 2012 Elsevier Inc. All rights reserved.

  9. Transverse Spin Physics: Recent Developments

    International Nuclear Information System (INIS)

    Yuan, Feng

    2008-01-01

    Transverse-spin physics has been very active and rapidly developing in the last few years. In this talk, I will briefly summarize recent theoretical developments, focusing on the associated QCD dynamics in transverse spin physics

  10. A stochastic picture of spin

    International Nuclear Information System (INIS)

    Faris, W.G.

    1981-01-01

    Dankel has shown how to incorporate spin into stochastic mechanics. The resulting non-local hidden variable theory gives an appealing picture of spin correlation experiments in which Bell's inequality is violated. (orig.)

  11. Muonium spin exchange in spin-polarized media: Spin-flip and -nonflip collisions

    International Nuclear Information System (INIS)

    Senba, M.

    1994-01-01

    The transverse relaxation of the muon spin in muonium due to electron spin exchange with a polarized spin-1/2 medium is investigated. Stochastic calculations, which assume that spin exchange is a Poisson process, are carried out for the case where the electron spin polarization of the medium is on the same axis as the applied field. Two precession signals of muonium observed in intermediate fields (B>30 G) are shown to have different relaxation rates which depend on the polarization of the medium. Furthermore, the precession frequencies are shifted by an amount which depends on the spin-nonflip rate. From the two relaxation rates and the frequency shift in intermediate fields, one can determine (i) the encounter rate of muonium and the paramagnetic species, (ii) the polarization of the medium, and most importantly (iii) the quantum-mechanical phase shift (and its sign) associated with the potential energy difference between electron singlet and triplet encounters. Effects of spin-nonflip collisions on spin dynamics are discussed for non-Poisson as well as Poisson processes. In unpolarized media, the time evolution of the muon spin in muonium is not influenced by spin-nonflip collisions, if the collision process is Poissonian. This seemingly obvious statement is not true anymore in non-Poissonian processes, i.e., it is necessary to specify both spin-flip and spin-nonflip rates to fully characterize spin dynamics

  12. Antiferromagnetic spin-orbitronics

    KAUST Repository

    Manchon, Aurelien; Saidaoui, Hamed Ben Mohamed; Ghosh, Sumit

    2015-01-01

    Antiferromagnets have long remained an intriguing and exotic state of matter, whose application has been restricted to enabling interfacial exchange bias in metallic and tunneling spin-valves [1]. Their role in the expanding field of applied spintronics has been mostly passive and the in-depth investigation of their basic properties mostly considered from a fundamental perspective.

  13. Antiferromagnetic spin-orbitronics

    KAUST Repository

    Manchon, Aurelien

    2015-05-01

    Antiferromagnets have long remained an intriguing and exotic state of matter, whose application has been restricted to enabling interfacial exchange bias in metallic and tunneling spin-valves [1]. Their role in the expanding field of applied spintronics has been mostly passive and the in-depth investigation of their basic properties mostly considered from a fundamental perspective.

  14. Brookhaven: Spin result underlined

    Energy Technology Data Exchange (ETDEWEB)

    Anon.

    1990-09-15

    A recent experiment looking at violent proton-proton elastic scattering confirms, with high precision, earlier data which puzzled many theorists. Most pictures of strong interactions based on perturbative quark-gluon field theory (Quantum Chromodynamics, QCD) suggested that spin effects should disappear with energy and as the collisions become more violent.

  15. Nuclear Spin Relaxation

    Indian Academy of Sciences (India)

    IAS Admin

    ments have shown that in some cases the nuclear spin systems may be held in special configurations called .... these methods have been commercialized, and used for clinical trials, in which hyperpolarized NMR is used to .... symmetric under exchange, meaning that exchanging the two nuclei leaves the state unchanged.

  16. Nuclear spin-off

    International Nuclear Information System (INIS)

    1981-11-01

    This booklet gives examples of 'nuclear spin off', from research programmes carried out for the UKAEA, under the following headings; non destructive testing; tribology; environmental protection; flow measurement; material sciences; mechanical engineering; marine services; biochemical technology; electronic instrumentation. (U.K.)

  17. Spin and isospin modes

    International Nuclear Information System (INIS)

    Suzuki, T.; Sagawa, H.

    2000-01-01

    Complete text of publication follows. Spin and isospin modes in nuclei are investigated. We discuss some of the following topics. 1. Spin-dipole excitations in 12 C and 16 O are studied (1). Effects of tensor and spin-orbit interactions on the distribution of the strengths are investigated, and neutral current neutrino scattering cross sections in 16 O are obtained for heavy-flavor neutrinos from the supernovae. 2. Gamow-Teller (GT) and spin-dipole (SD) modes in 208 Bi are investigated. Quenching and fragmentation of the GT strength are discussed (2). SD excitations and electric dipole (E1) transitions between the GT and SD states are studied (3). Calculated E1 strengths are compared with the sum rule values obtained within the 1p-1h and 1p-1h + 2p-2h configuration spaces. 3. Coulomb displacement energy (CDE) of the IAS of 14 Be is calculated, and the effects of the halo on the CDE and the configuration of the halo state are investigated. 4. Spreading width of IAS and isospin dependence of the width are investigated (4). Our formula for the width explains very well the observed isospin dependence (5). (author)

  18. Spin physics at ELSA

    International Nuclear Information System (INIS)

    Althoff, K.H.

    1989-01-01

    In 1987 the new Bonn stretcher accelerator ELSA came into operation. In this paper a short description of the accelerator and the three experimental facilities PHOENICS, ELAN and SAPHIR is given. The determination of spin observables is one of the main subjects of the experimental program. Some experiments are discussed in more detail

  19. Spin physics in semiconductors

    CERN Document Server

    Dyakonov, Mikhail I

    2008-01-01

    This book describes beautiful optical and transport phenomena related to the electron and nuclear spins in semiconductors with emphasis on a clear presentation of the physics involved. Recent results on quantum wells and quantum dots are reviewed. The book is intended for students and researchers in the fields of semiconductor physics and nanoelectronics.

  20. Brookhaven: Spin result underlined

    International Nuclear Information System (INIS)

    Anon.

    1990-01-01

    A recent experiment looking at violent proton-proton elastic scattering confirms, with high precision, earlier data which puzzled many theorists. Most pictures of strong interactions based on perturbative quark-gluon field theory (Quantum Chromodynamics, QCD) suggested that spin effects should disappear with energy and as the collisions become more violent

  1. Spin polarizability of hyperons

    Indian Academy of Sciences (India)

    K B VIJAYA KUMAR. Department of Physics, Mangalore University, Mangalagangothri 574 199, India. E-mail: kbvijayakumar@yahoo.com. DOI: 10.1007/s12043-014-0869-4; ePublication: 4 November 2014. Abstract. We review the recent progress of the theoretical understanding of spin polarizabilities of the hyperon in the ...

  2. The invariance of spin

    International Nuclear Information System (INIS)

    Bramson, B.D.

    1978-01-01

    An isolated system in general relativity makes a transition between stationary states. It is shown that the spin vectors of the system, long before and long after the emission of radiation, are supertranslation invariant and, hence, independent of the choice of Minkowski observation space. (author)

  3. Measuring absolute spin polarization in dissolution-DNP by Spin PolarimetrY Magnetic Resonance (SPY-MR).

    Science.gov (United States)

    Vuichoud, Basile; Milani, Jonas; Chappuis, Quentin; Bornet, Aurélien; Bodenhausen, Geoffrey; Jannin, Sami

    2015-11-01

    Dynamic nuclear polarization at 1.2 K and 6.7 T allows one to achieve spin temperatures on the order of a few millikelvin, so that the high-temperature approximation (ΔEPolarimetrY Magnetic Resonance (SPY-MR), is illustrated for various pairs of (13)C spins (I, S) in acetate and pyruvate. Copyright © 2015 The Authors. Published by Elsevier Inc. All rights reserved.

  4. Spin Injection in Indium Arsenide

    Directory of Open Access Journals (Sweden)

    Mark eJohnson

    2015-08-01

    Full Text Available In a two dimensional electron system (2DES, coherent spin precession of a ballistic spin polarized current, controlled by the Rashba spin orbit interaction, is a remarkable phenomenon that’s been observed only recently. Datta and Das predicted this precession would manifest as an oscillation in the source-drain conductance of the channel in a spin-injected field effect transistor (Spin FET. The indium arsenide single quantum well materials system has proven to be ideal for experimental confirmation. The 2DES carriers have high mobility, low sheet resistance, and high spin orbit interaction. Techniques for electrical injection and detection of spin polarized carriers were developed over the last two decades. Adapting the proposed Spin FET to the Johnson-Silsbee nonlocal geometry was a key to the first experimental demonstration of gate voltage controlled coherent spin precession. More recently, a new technique measured the oscillation as a function of channel length. This article gives an overview of the experimental phenomenology of the spin injection technique. We then review details of the application of the technique to InAs single quantum well (SQW devices. The effective magnetic field associated with Rashba spin-orbit coupling is described, and a heuristic model of coherent spin precession is presented. The two successful empirical demonstrations of the Datta Das conductance oscillation are then described and discussed.

  5. An overview of spin physics

    International Nuclear Information System (INIS)

    Prescott, C.Y.

    1991-07-01

    Spin physics is playing an increasingly important role in high energy experiments and theory. This review looks at selected topics in high energy spin physics that were discussed at the 9th International Symposium on High Energy Spin Physics at Bonn in September 1990

  6. Mechanical generation of spin current

    Directory of Open Access Journals (Sweden)

    Mamoru eMatsuo

    2015-07-01

    Full Text Available We focus the recent results on spin-current generation from mechanical motion such as rigid rotation and elastic deformations. Spin transport theory in accelerating frames is constructed by using the low energy expansion of the generally covariant Dirac equation. Related issues on spin-manipulation by mechanical rotation are also discussed.

  7. Spin Transport in Semiconductor heterostructures

    International Nuclear Information System (INIS)

    Marinescu, Domnita Catalina

    2011-01-01

    The focus of the research performed under this grant has been the investigation of spin transport in magnetic semiconductor heterostructures. The interest in these systems is motivated both by their intriguing physical properties, as the physical embodiment of a spin-polarized Fermi liquid, as well as by their potential applications as spintronics devices. In our work we have analyzed several different problems that affect the spin dynamics in single and bi-layer spin-polarized two-dimensional (2D) systems. The topics of interests ranged from the fundamental aspects of the electron-electron interactions, to collective spin and charge density excitations and spin transport in the presence of the spin-orbit coupling. The common denominator of these subjects is the impact at the macroscopic scale of the spin-dependent electron-electron interaction, which plays a much more subtle role than in unpolarized electron systems. Our calculations of several measurable parameters, such as the excitation frequencies of magneto-plasma modes, the spin mass, and the spin transresistivity, propose realistic theoretical estimates of the opposite-spin many-body effects, in particular opposite-spin correlations, that can be directly connected with experimental measurements.

  8. Quantum electrodynamics of particles with arbitrary spin

    International Nuclear Information System (INIS)

    Green, H.S.

    1978-01-01

    A generalization of quantum electrodynamics is developed for particles of higher spin, with careful attention to the requirements of consistency, causality, unitarity and renormalizability. It is shown that field equations studied previously by the author are expressible in arbitrarily many different forms, which are equivalent in the absence of electromagnetic interactions, but not when electromagnetic coupling is introduced in a gauge-invariant way. A form is chosen which satisfies the requirements of casuality. It is shown how to define a particle density, which is positive-definite in the subspace spanned by solutions of the field equation, and satisifies a Lorentz-invariant conservation law. The quantization and renormalization of the resulting electrodynamics is studied, and is found to require only minor modifications of the existing theory for particles of spin 1/2

  9. 7 CFR 1709.2 Policy. - [Reserved

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 11 2010-01-01 2010-01-01 false [Reserved] 1709.2 Policy. Section 1709.2 Policy. Agriculture Regulations of the Department of Agriculture (Continued) RURAL UTILITIES SERVICE, DEPARTMENT OF AGRICULTURE ASSISTANCE TO HIGH ENERGY COST COMMUNITIES General Requirements § 1709.2 Policy. [Reserved] ...

  10. 100% spin accumulation in non-half-metallic ferromagnet-semiconductor junctions

    International Nuclear Information System (INIS)

    Petukhov, A G; Niggemann, J; Smelyanskiy, V N; Osipov, V V

    2007-01-01

    We show that the spin polarization of electron density in non-magnetic degenerate semiconductors can achieve 100%. The effect of 100% spin accumulation does not require a half-metallic ferromagnetic contact and can be realized in ferromagnet-semiconductor FM-n + -n junctions even at moderate spin selectivity of the FM-n + contact when the electrons with spin 'up' are extracted from n semiconductor through the heavily doped n + layer into the ferromagnet and the electrons with spin 'down' are accumulated near the n + -n interface. We derived a general equation relating spin polarization of the current to that of the electron density in non-magnetic semiconductors. We found that the effect of complete spin polarization is achieved near the n + -n interface when the concentration of the spin 'up' electrons tends to zero in this region while the diffusion current of these electrons remains finite

  11. Risk reserve constrained economic dispatch model with wind power penetration

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, W.; Sun, H.; Peng, Y. [Department of Electrical and Electronics Engineering, Dalian University of Technology, Dalian, 116024 (China)

    2010-12-15

    This paper develops a modified economic dispatch (ED) optimization model with wind power penetration. Due to the uncertain nature of wind speed, both overestimation and underestimation of the available wind power are compensated using the up and down spinning reserves. In order to determine both of these two reserve demands, the risk-based up and down spinning reserve constraints are presented considering not only the uncertainty of available wind power, but also the load forecast error and generator outage rates. The predictor-corrector primal-dual interior point method is utilized to solve the proposed ED model. Simulation results of a system with ten conventional generators and one wind farm demonstrate the effectiveness of the proposed method. (authors)

  12. Optical switching of nuclear spin-spin couplings in semiconductors.

    Science.gov (United States)

    Goto, Atsushi; Ohki, Shinobu; Hashi, Kenjiro; Shimizu, Tadashi

    2011-07-05

    Two-qubit operation is an essential part of quantum computation. However, solid-state nuclear magnetic resonance quantum computing has not been able to fully implement this functionality, because it requires a switchable inter-qubit coupling that controls the time evolutions of entanglements. Nuclear dipolar coupling is beneficial in that it is present whenever nuclear-spin qubits are close to each other, while it complicates two-qubit operation because the qubits must remain decoupled to prevent unwanted couplings. Here we introduce optically controllable internuclear coupling in semiconductors. The coupling strength can be adjusted externally through light power and even allows on/off switching. This feature provides a simple way of switching inter-qubit couplings in semiconductor-based quantum computers. In addition, its long reach compared with nuclear dipolar couplings allows a variety of options for arranging qubits, as they need not be next to each other to secure couplings.

  13. Spin-orbit induced electronic spin separation in semiconductor nanostructures.

    Science.gov (United States)

    Kohda, Makoto; Nakamura, Shuji; Nishihara, Yoshitaka; Kobayashi, Kensuke; Ono, Teruo; Ohe, Jun-ichiro; Tokura, Yasuhiro; Mineno, Taiki; Nitta, Junsaku

    2012-01-01

    The demonstration of quantized spin splitting by Stern and Gerlach is one of the most important experiments in modern physics. Their discovery was the precursor of recent developments in spin-based technologies. Although electrical spin separation of charged particles is fundamental in spintronics, in non-uniform magnetic fields it has been difficult to separate the spin states of charged particles due to the Lorentz force, as well as to the insufficient and uncontrollable field gradients. Here we demonstrate electronic spin separation in a semiconductor nanostructure. To avoid the Lorentz force, which is inevitably induced when an external magnetic field is applied, we utilized the effective non-uniform magnetic field which originates from the Rashba spin-orbit interaction in an InGaAs-based heterostructure. Using a Stern-Gerlach-inspired mechanism, together with a quantum point contact, we obtained field gradients of 10(8) T m(-1) resulting in a highly polarized spin current.

  14. Spin Relaxation and Manipulation in Spin-orbit Qubits

    Science.gov (United States)

    Borhani, Massoud; Hu, Xuedong

    2012-02-01

    We derive a generalized form of the Electric Dipole Spin Resonance (EDSR) Hamiltonian in the presence of the spin-orbit interaction for single spins in an elliptic quantum dot (QD) subject to an arbitrary (in both direction and magnitude) applied magnetic field. We predict a nonlinear behavior of the Rabi frequency as a function of the magnetic field for sufficiently large Zeeman energies, and present a microscopic expression for the anisotropic electron g-tensor. Similarly, an EDSR Hamiltonian is devised for two spins confined in a double quantum dot (DQD). Finally, we calculate two-electron-spin relaxation rates due to phonon emission, for both in-plane and perpendicular magnetic fields. Our results have immediate applications to current EDSR experiments on nanowire QDs, g-factor optimization of confined carriers, and spin decay measurements in DQD spin-orbit qubits.

  15. Excitation of coherent propagating spin waves by pure spin currents.

    Science.gov (United States)

    Demidov, Vladislav E; Urazhdin, Sergei; Liu, Ronghua; Divinskiy, Boris; Telegin, Andrey; Demokritov, Sergej O

    2016-01-28

    Utilization of pure spin currents not accompanied by the flow of electrical charge provides unprecedented opportunities for the emerging technologies based on the electron's spin degree of freedom, such as spintronics and magnonics. It was recently shown that pure spin currents can be used to excite coherent magnetization dynamics in magnetic nanostructures. However, because of the intrinsic nonlinear self-localization effects, magnetic auto-oscillations in the demonstrated devices were spatially confined, preventing their applications as sources of propagating spin waves in magnonic circuits using these waves as signal carriers. Here, we experimentally demonstrate efficient excitation and directional propagation of coherent spin waves generated by pure spin current. We show that this can be achieved by using the nonlocal spin injection mechanism, which enables flexible design of magnetic nanosystems and allows one to efficiently control their dynamic characteristics.

  16. Are uranium reserves adequate?

    International Nuclear Information System (INIS)

    Anon.

    2006-01-01

    Against a backdrop of growing concerns about global warming and geopolitical pressures on fossil energies, especially natural gas and oil, interest in nuclear power has revived considerably. Conscious of its addiction to oil and reeling from a series of gigantic blackouts, the United States, in the words of its president, must 'aggressively move forward with the construction of nuclear power plants'. Some European countries have approved new power plant construction (Finland and France), while the more reserved ones (Belgium, Germany and Sweden) have begun to show a change in attitude. Asia, meanwhile, is host to the planet's largest number of potential nuclear construction projects in this first half of the 21. century. All these signs point to a sharp rise in uranium consumption, the basic fuel for these plants. But are there enough resources to support a nuclear revival on a planetary scale? The publication of the Red Book on uranium in late May 2006 was an opportunity for Thierry Dujardin, Deputy Director of Science and Development at the OECD's Nuclear Energy Agency, to take stock of resources. He gives his opinion in this paper

  17. Spin current and spin transfer torque in ferromagnet/superconductor spin valves

    Science.gov (United States)

    Moen, Evan; Valls, Oriol T.

    2018-05-01

    Using fully self-consistent methods, we study spin transport in fabricable spin valve systems consisting of two magnetic layers, a superconducting layer, and a spacer normal layer between the ferromagnets. Our methods ensure that the proper relations between spin current gradients and spin transfer torques are satisfied. We present results as a function of geometrical parameters, interfacial barrier values, misalignment angle between the ferromagnets, and bias voltage. Our main results are for the spin current and spin accumulation as functions of position within the spin valve structure. We see precession of the spin current about the exchange fields within the ferromagnets, and penetration of the spin current into the superconductor for biases greater than the critical bias, defined in the text. The spin accumulation exhibits oscillating behavior in the normal metal, with a strong dependence on the physical parameters both as to the structure and formation of the peaks. We also study the bias dependence of the spatially averaged spin transfer torque and spin accumulation. We examine the critical-bias effect of these quantities, and their dependence on the physical parameters. Our results are predictive of the outcome of future experiments, as they take into account imperfect interfaces and a realistic geometry.

  18. Spin injection and spin accumulation in all-metal mesoscopic spin valves

    NARCIS (Netherlands)

    Jedema, FJ; Nijboer, MS; Filip, AT; van Wees, BJ

    2003-01-01

    We study the electrical injection and detection of spin accumulation in lateral ferromagnetic-metal-nonmagnetic-metal-ferromagnetic-metal (F/N/F) spin valve devices with transparent interfaces. Different ferromagnetic metals, Permalloy (Py), cobalt (Co), and nickel (Ni), are used as electrical spin

  19. Spin current evolution in the separated spin-up and spin-down quantum hydrodynamics

    International Nuclear Information System (INIS)

    Trukhanova, Mariya Iv.

    2015-01-01

    We have developed a method of quantum hydrodynamics (QHD) that describes particles with spin-up and with spin-down in separate. We have derived the equation of the spin current evolution as a part of the set of the quantum hydrodynamics equations that treat particles with different projection of spin on the preferable direction as two different species. We have studied orthogonal propagation of waves in the external magnetic field and determined the contribution of quantum corrections due to the Bohm potential and to magnetization energy of particles with different projections of spin in the spin-current wave dispersion. We have analyzed the limits of weak and strong magnetic fields. - Highlights: • We derive the spin current equation for particles with different projection of spin. • We predict the contribution of Bohm potential to the dynamics of spin current. • We derive the spin-current wave in the system of spin-polarized particles. • We study the propagation of spin-acoustic wave in magnetized dielectrics.

  20. Spin Torques in Systems with Spin Filtering and Spin Orbit Interaction

    KAUST Repository

    Ortiz Pauyac, Christian

    2016-01-01

    filtering. In Chap. 3 we discuss the Rashba torque in ferromagnetic films, and in Chap. 4 we study spin Hall effect and spin swapping in ferromagnetic films, exploring the nature of spin-orbit torques based on these mechanisms. Conclusions and perspectives

  1. Photon-gated spin transistor

    OpenAIRE

    Li, Fan; Song, Cheng; Cui, Bin; Peng, Jingjing; Gu, Youdi; Wang, Guangyue; Pan, Feng

    2017-01-01

    Spin-polarized field-effect transistor (spin-FET), where a dielectric layer is generally employed for the electrical gating as the traditional FET, stands out as a seminal spintronic device under the miniaturization trend of electronics. It would be fundamentally transformative if optical gating was used for spin-FET. We report a new type of spin-polarized field-effect transistor (spin-FET) with optical gating, which is fabricated by partial exposure of the (La,Sr)MnO3 channel to light-emitti...

  2. Extended higher-spin superalgebras and their massless representations

    Energy Technology Data Exchange (ETDEWEB)

    Konstein, S E; Vasiliev, M A [AN SSSR, Moscow (USSR). Fizicheskij Inst.

    1990-02-12

    Three two-parameter sequences of infinite-dimensional extended higher-spin superalgebras are constructed, which give rise to consistent equations of motion of interacting gauge fields of all spins in four dimensions. In the Yang-Mills sector of spin-1 gauge fields, these higher-spin superalgebras reduce to u(n) + u(m), o(n) + o(m) and usp(n) + usp(m) with arbitrary integer parameters n {ge} 0 and m {ge} 0 (n and m are assumed to be even for symplectic algebras). Massless unitary representations of the proposed higher-spin superalgebras are analyzed. It is shown that all these superalgebras obey the admissibility condition which requires them to possess massless unitary representations with just the same spectra of spins as follows from the structure of the related higher-spin gauge fields. We argue that the infinite-dimensional (super)algebras listed in this article classify all possible higher-spin rigid (super)symmetries in four dimensions. (orig.).

  3. Magnon detection using a ferroic collinear multilayer spin valve.

    Science.gov (United States)

    Cramer, Joel; Fuhrmann, Felix; Ritzmann, Ulrike; Gall, Vanessa; Niizeki, Tomohiko; Ramos, Rafael; Qiu, Zhiyong; Hou, Dazhi; Kikkawa, Takashi; Sinova, Jairo; Nowak, Ulrich; Saitoh, Eiji; Kläui, Mathias

    2018-03-14

    Information transport and processing by pure magnonic spin currents in insulators is a promising alternative to conventional charge-current-driven spintronic devices. The absence of Joule heating and reduced spin wave damping in insulating ferromagnets have been suggested for implementing efficient logic devices. After the successful demonstration of a majority gate based on the superposition of spin waves, further components are required to perform complex logic operations. Here, we report on magnetization orientation-dependent spin current detection signals in collinear magnetic multilayers inspired by the functionality of a conventional spin valve. In Y 3 Fe 5 O 12 |CoO|Co, we find that the detection amplitude of spin currents emitted by ferromagnetic resonance spin pumping depends on the relative alignment of the Y 3 Fe 5 O 12 and Co magnetization. This yields a spin valve-like behavior with an amplitude change of 120% in our systems. We demonstrate the reliability of the effect and identify its origin by both temperature-dependent and power-dependent measurements.

  4. Optically induced dynamic nuclear spin polarisation in diamond

    International Nuclear Information System (INIS)

    Scheuer, Jochen; Naydenov, Boris; Jelezko, Fedor; Schwartz, Ilai; Chen, Qiong; Plenio, Martin B; Schulze-Sünninghausen, David; Luy, Burkhard; Carl, Patrick; Höfer, Peter; Retzker, Alexander; Sumiya, Hitoshi; Isoya, Junichi

    2016-01-01

    The sensitivity of magnetic resonance imaging (MRI) depends strongly on nuclear spin polarisation and, motivated by this observation, dynamical nuclear spin polarisation has recently been applied to enhance MRI protocols (Kurhanewicz et al 2011 Neoplasia 13 81). Nuclear spins associated with the 13 C carbon isotope (nuclear spin I = 1/2) in diamond possess uniquely long spin lattice relaxation times (Reynhardt and High 2011 Prog. Nucl. Magn. Reson. Spectrosc. 38 37). If they are present in diamond nanocrystals, especially when strongly polarised, they form a promising contrast agent for MRI. Current schemes for achieving nuclear polarisation, however, require cryogenic temperatures. Here we demonstrate an efficient scheme that realises optically induced 13 C nuclear spin hyperpolarisation in diamond at room temperature and low ambient magnetic field. Optical pumping of a nitrogen-vacancy centre creates a continuously renewable electron spin polarisation which can be transferred to surrounding 13 C nuclear spins. Importantly for future applications we also realise polarisation protocols that are robust against an unknown misalignment between magnetic field and crystal axis. (paper)

  5. Efficient spin transport through polyaniline

    Science.gov (United States)

    Mendes, J. B. S.; Alves Santos, O.; Gomes, J. P.; Assis, H. S.; Felix, J. F.; Rodríguez-Suárez, R. L.; Rezende, S. M.; Azevedo, A.

    2017-01-01

    By using the spin pumping process, we show that it is possible to transport a pure spin current across layers of conducting polyaniline (PANI) with several hundred nanometers sandwiched between a film of the ferrimagnetic insulator yttrium iron garnet (YIG) and a thin layer of platinum. The spin current generated by microwave-driven ferromagnetic resonance of the YIG film, injected through the YIG/PANI interface, crosses the whole PANI layer and then is injected into the Pt layer. By means of the inverse spin Hall effect in the Pt, the spin current is converted into charge current and electrically detected as a dc voltage. We measured a spin diffusion length in PANI of 590 ± 40 nm, which is very large compared with normal metals, demonstrating that PANI can be used as an efficient spin current conductor and poor charge current conductor, opening the path towards spintronics applications based in this very attractive material.

  6. Performance assessment of a new laser system for efficient spin exchange optical pumping in a spin maser measurement of 129Xe EDM

    International Nuclear Information System (INIS)

    Funayama, C.; Furukawa, T.; Sato, T.; Ichikawa, Y.; Ohtomo, Y.; Sakamoto, Y.; Kojima, S.; Suzuki, T.; Hirao, C.; Chikamori, M.; Hikota, E.; Tsuchiya, M.; Yoshimi, A.; Bidinosti, C. P.; Ino, T.; Ueno, H.; Matsuo, Y.; Fukuyama, T.; Asahi, K.

    2015-01-01

    We demonstrate spin-exchange optical pumping of 129 Xe atoms with our newly made laser system. The new laser system was prepared to provide higher laser power required for the stable operation of spin maser oscillations in the 129 Xe EDM experiment. We studied the optimum cell temperature and pumping laser power to improve the degree of 129 Xe spin polarization. The best performance was achieved at the cell temperature of 100 ∘ C with the presently available laser power of 1 W. The results show that a more intense laser is required for further improvement of the spin polarization at higher cell temperatures in our experiment

  7. Spin Funneling for Enhanced Spin Injection into Ferromagnets

    Science.gov (United States)

    Sayed, Shehrin; Diep, Vinh Q.; Camsari, Kerem Yunus; Datta, Supriyo

    2016-07-01

    It is well-established that high spin-orbit coupling (SOC) materials convert a charge current density into a spin current density which can be used to switch a magnet efficiently and there is increasing interest in identifying materials with large spin Hall angle for lower switching current. Using experimentally benchmarked models, we show that composite structures can be designed using existing spin Hall materials such that the effective spin Hall angle is larger by an order of magnitude. The basic idea is to funnel spins from a large area of spin Hall material into a small area of ferromagnet using a normal metal with large spin diffusion length and low resistivity like Cu or Al. We show that this approach is increasingly effective as magnets get smaller. We avoid unwanted charge current shunting by the low resistive NM layer utilizing the newly discovered phenomenon of pure spin conduction in ferromagnetic insulators via magnon diffusion. We provide a spin circuit model for magnon diffusion in FMI that is benchmarked against recent experiments and theory.

  8. Doppler Velocimetry of Current Driven Spin Helices in a Two-Dimensional Electron Gas

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Luyi [Univ. of California, Berkeley, CA (United States)

    2013-05-17

    Spins in semiconductors provide a pathway towards the development of spin-based electronics. The appeal of spin logic devices lies in the fact that the spin current is even under time reversal symmetry, yielding non-dissipative coupling to the electric field. To exploit the energy-saving potential of spin current it is essential to be able to control it. While recent demonstrations of electrical-gate control in spin-transistor configurations show great promise, operation at room temperature remains elusive. Further progress requires a deeper understanding of the propagation of spin polarization, particularly in the high mobility semiconductors used for devices. This dissertation presents the demonstration and application of a powerful new optical technique, Doppler spin velocimetry, for probing the motion of spin polarization at the level of 1 nm on a picosecond time scale. We discuss experiments in which this technique is used to measure the motion of spin helices in high mobility n-GaAs quantum wells as a function of temperature, in-plane electric field, and photoinduced spin polarization amplitude. We find that the spin helix velocity changes sign as a function of wave vector and is zero at the wave vector that yields the largest spin lifetime. This observation is quite striking, but can be explained by the random walk model that we have developed. We discover that coherent spin precession within a propagating spin density wave is lost at temperatures near 150 K. This finding is critical to understanding why room temperature operation of devices based on electrical gate control of spin current has so far remained elusive. We report that, at all temperatures, electron spin polarization co-propagates with the high-mobility electron sea, even when this requires an unusual form of separation of spin density from photoinjected electron density. Furthermore, although the spin packet co-propagates with the two-dimensional electron gas, spin diffusion is strongly

  9. Shot noise of spin current and spin transfer torque

    Science.gov (United States)

    Yu, Yunjin; Zhan, Hongxin; Wan, Langhui; Wang, Bin; Wei, Yadong; Sun, Qingfeng; Wang, Jian

    2013-04-01

    We report the theoretical investigation of the shot noise of the spin current (Sσ) and the spin transfer torque (Sτ) for non-collinear spin polarized transport in a spin-valve device which consists of a normal scattering region connected by two ferromagnetic electrodes (MNM system). Our theory was developed using the non-equilibrium Green’s function method, and general nonlinear Sσ - V and Sτ - V relations were derived as a function of the angle θ between the magnetizations of two leads. We have applied our theory to a quantum dot system with a resonant level coupled with two ferromagnetic electrodes. It was found that, for the MNM system, the auto-correlation of the spin current is enough to characterize the fluctuation of the spin current. For a system with three ferromagnetic layers, however, both auto-correlation and cross-correlation of the spin current are needed to characterize the noise of the spin current. For a quantum dot with a resonant level, the derivative of spin torque with respect to bias voltage is proportional to sinθ when the system is far away from resonance. When the system is near resonance, the spin transfer torque becomes a non-sinusoidal function of θ. The derivative of the noise of the spin transfer torque with respect to the bias voltage Nτ behaves differently when the system is near or far away from resonance. Specifically, the differential shot noise of the spin transfer torque Nτ is a concave function of θ near resonance while it becomes a convex function of θ far away from resonance. For certain bias voltages, the period Nτ(θ) becomes π instead of 2π. For small θ, it was found that the differential shot noise of the spin transfer torque is very sensitive to the bias voltage and the other system parameters.

  10. Shot noise of spin current and spin transfer torque

    International Nuclear Information System (INIS)

    Yu Yunjin; Zhan Hongxin; Wan Langhui; Wang Bin; Wei Yadong; Sun Qingfeng; Wang Jian

    2013-01-01

    We report the theoretical investigation of the shot noise of the spin current (S σ ) and the spin transfer torque (S τ ) for non-collinear spin polarized transport in a spin-valve device which consists of a normal scattering region connected by two ferromagnetic electrodes (MNM system). Our theory was developed using the non-equilibrium Green’s function method, and general nonlinear S σ − V and S τ − V relations were derived as a function of the angle θ between the magnetizations of two leads. We have applied our theory to a quantum dot system with a resonant level coupled with two ferromagnetic electrodes. It was found that, for the MNM system, the auto-correlation of the spin current is enough to characterize the fluctuation of the spin current. For a system with three ferromagnetic layers, however, both auto-correlation and cross-correlation of the spin current are needed to characterize the noise of the spin current. For a quantum dot with a resonant level, the derivative of spin torque with respect to bias voltage is proportional to sinθ when the system is far away from resonance. When the system is near resonance, the spin transfer torque becomes a non-sinusoidal function of θ. The derivative of the noise of the spin transfer torque with respect to the bias voltage N τ behaves differently when the system is near or far away from resonance. Specifically, the differential shot noise of the spin transfer torque N τ is a concave function of θ near resonance while it becomes a convex function of θ far away from resonance. For certain bias voltages, the period N τ (θ) becomes π instead of 2π. For small θ, it was found that the differential shot noise of the spin transfer torque is very sensitive to the bias voltage and the other system parameters. (paper)

  11. Quasiclassical Theory of Spin Imbalance in a Normal Metal-Superconductor Heterostructure with a Spin-Active Interface

    International Nuclear Information System (INIS)

    Shevtsov, O; Löfwander, T

    2014-01-01

    Non-equilibrium phenomena in superconductors have attracted much attention since the first experiments on charge imbalance in the early 1970's. Nowadays a new promising line of research lies at an intersection between superconductivity and spintronics. Here we develop a quasiclassical theory of a single junction between a normal metal and a superconductor with a spin-active interface at finite bias voltages. Due to spin-mixing and spin-filtering effects of the interface a non-equilibrium magnetization (or spin imbalance) is induced at the superconducting side of the junction, which relaxes to zero in the bulk. A peculiar feature of the system is the presence of interface-induced Andreev bound states, which influence the magnitude and the decay length of spin imbalance. Recent experiments on spin and charge density separation in superconducting wires required external magnetic field for observing a spin signal via non-local measurements. Here, we propose an alternative way to observe spin imbalance without applying magnetic field

  12. Nucleon spin structure functions

    International Nuclear Information System (INIS)

    Close, F.E.

    1989-01-01

    There has been recent excitement arising from the claim by the EMC collaboration that none of the proton's spin is carried by quarks. There are many textbooks, including those written by some members of this audience which assert that the proton's spin is carried by quarks. I will review the history of deep inelastic scattering of polarized leptons from polarized protons, culminating in this most recent dramatic claim. I will show that, for the last decade, data have appeared consistent with predictions of the quark model and highlight what the new and potentially exciting data are. I will conclude with suggestions for the future, and discuss the polarization dependence of inclusive hadron production. 35 refs

  13. Art of spin decomposition

    International Nuclear Information System (INIS)

    Chen Xiangsong; Sun Weimin; Wang Fan; Goldman, T.

    2011-01-01

    We analyze the problem of spin decomposition for an interacting system from a natural perspective of constructing angular-momentum eigenstates. We split, from the total angular-momentum operator, a proper part which can be separately conserved for a stationary state. This part commutes with the total Hamiltonian and thus specifies the quantum angular momentum. We first show how this can be done in a gauge-dependent way, by seeking a specific gauge in which part of the total angular-momentum operator vanishes identically. We then construct a gauge-invariant operator with the desired property. Our analysis clarifies what is the most pertinent choice among the various proposals for decomposing the nucleon spin. A similar analysis is performed for extracting a proper part from the total Hamiltonian to construct energy eigenstates.

  14. Spin and Madelung fluid

    International Nuclear Information System (INIS)

    Salesi, G.

    1995-07-01

    Starting from the Pauli current the decomposition of the non-relativistic local velocity has been obtained in two parts (in the ordinary tensorial language): one parallel and the other orthogonal to the impulse. The former is recognized to be the classical part, that is, the center-of-mass (CM) velocity, and the latter the quantum one, that is, the velocity of the motion in the CM frame (namely, the internal spin motion or Zitterbewegung). Inserting this complete, composite expression of the velocity into the kinetic energy term of the classical non-relativistic (i.e. Newtonian) Lagrangian, the author straightforwardly get the appearance of the so called quantum potential associates as it is known, to the Madelung fluid. In such a way, the quantum mechanical behaviour of particles appears to be strictly correlated to the existence of spin and Zitterbewegung

  15. Non-Abelian hydrodynamics and the flow of spin in spin-orbit coupled substances

    International Nuclear Information System (INIS)

    Leurs, B.W.A.; Nazario, Z.; Santiago, D.I.; Zaanen, J.

    2008-01-01

    Motivated by the heavy ion collision experiments there is much activity in studying the hydrodynamical properties of non-Abelian (quark-gluon) plasmas. A major question is how to deal with color currents. Although not widely appreciated, quite similar issues arise in condensed matter physics in the context of the transport of spins in the presence of spin-orbit coupling. The key insight is that the Pauli Hamiltonian governing the leading relativistic corrections in condensed matter systems can be rewritten in a language of SU(2) covariant derivatives where the role of the non-Abelian gauge fields is taken by the physical electromagnetic fields: the Pauli system can be viewed as Yang-Mills quantum-mechanics in a 'fixed frame', and it can be viewed as an 'analogous system' for non-Abelian transport in the same spirit as Volovik's identification of the He superfluids as analogies for quantum fields in curved space time. We take a similar perspective as Jackiw and coworkers in their recent study of non-Abelian hydrodynamics, twisting the interpretation into the 'fixed frame' context, to find out what this means for spin transport in condensed matter systems. We present an extension of Jackiw's scheme: non-Abelian hydrodynamical currents can be factored in a 'non-coherent' classical part, and a coherent part requiring macroscopic non-Abelian quantum entanglement. Hereby it becomes particularly manifest that non-Abelian fluid flow is a much richer affair than familiar hydrodynamics, and this permits us to classify the various spin transport phenomena in condensed matter physics in an unifying framework. The 'particle based hydrodynamics' of Jackiw et al. is recognized as the high temperature spin transport associated with semiconductor spintronics. In this context the absence of faithful hydrodynamics is well known, but in our formulation it is directly associated with the fact that the covariant conservation of non-Abelian currents turns into a disastrous non

  16. 78 FR 50038 - National Estuarine Research Reserve System

    Science.gov (United States)

    2013-08-16

    ....33(c), the revised plan meets the reserve's requirements for compliance. The Wells Reserve Management... Reserve System AGENCY: Estuarine Reserves Division, Office of Ocean and Coastal Resource Management.... ACTION: Notice of Public Comment Period for the Wells, Maine National Estuarine Research Reserve...

  17. 41 CFR 105-74.301 - [Reserved

    Science.gov (United States)

    2010-07-01

    ... 41 Public Contracts and Property Management 3 2010-07-01 2010-07-01 false [Reserved] 105-74.301 Section 105-74.301 Public Contracts and Property Management Federal Property Management Regulations System...-GOVERNMENTWIDE REQUIREMENTS FOR DRUG-FREE WORKPLACE (FINANCIAL ASSISTANCE) Requirements for Recipients Who Are...

  18. Pangaea, She No Spin

    Science.gov (United States)

    McDowell, M.

    2002-12-01

    Looking at lopsided Pangaea, shown imaginatively on many illustrated proposals, I wondered what would happen if the configuration were put in high relief on a globe and spun on axis. Then I wondered if the present configuration of land masses would itself balance as a spinning top. So I got two Replogle globes, two boxes of colored modeling clay sticks, and two fat knitting needles, to fit through the capped holes at the poles of the globes. The clay sticks I cut up into 3 mm. (1/8") slices, using a different color for each continent, and applied to the first globe, assuming the extreme exaggeration above the geoid, no matter how crude, would tell the story. Inserting one needle through the globe and securing it, I balanced the globe on the point of the needle and twirled it like a top. Result: Wobbly! Top end of needle gyrated unevenly, and here it was supposed to make a smooth precessional cone. Oh boy. For the second globe, I used a Scotese "free stuff" interpretation of Pangaea, which I had to augment considerably using USGS, DuToit, Irving and other references, fitting it on the globe and applying identical clay color slices to what I judged generally accepted land surfaces. Result: the thing would hardly stand up, let alone spin. Conclusion: Although a refinement of application on the "today" globe might eliminate nutation, creating a smoother spin, there is no way any refinement of Pangaea on the same size globe can come close. While the concept of a supercontinent may be viable, I theorize that it had to have evolved on a far smaller globe, where land mass could balance, and the "breakup" would not have caused us to wildly gyrate on our axis. Because Pangaea, she no spin.

  19. Nuclear spin off

    International Nuclear Information System (INIS)

    1984-01-01

    The focus for nuclear energy research in the UK has been mainly the generation of electricity. However, nuclear technology is also applied in many areas other than energy production. Nuclear Spin Off shows how technology has been transferred to industry, agriculture, medicine and other areas, creating considerable material benefit. Nuclear research has produced revolutionary new materials and measuring and detection techniques. This film shows a wide range of uses. (author)

  20. Spinning out a star.

    Science.gov (United States)

    Lord, Michael D; Mandel, Stanley W; Wager, Jeffrey D

    2002-06-01

    Spinouts rarely take off; most, in fact, fall into one or more of four traps that doom them from the start. Some companies spin out ventures that are too close to the core of their businesses, in effect selling off their crown jewels. Sometimes, a parent company uses the spinout primarily to pawn off debt or expenses or to quickly raise external capital for itself. Other times, a company may try to spin out an area of its business that lacks one or more of the critical legs of a successful company--a coherent business model, say, or a solid financial base. And in many cases, parent companies can't bring themselves to sever their ownership ties and give up control of their spinouts. R.J. Reynolds, the tobacco giant, managed to avoid these traps when it successfully spun out a most unlikely venture, the pharmaceutical company Targacept. As the story illustrates, the problem with spinouts is similar to the problem of rich children. Their parents have the wherewithal to spoil them or shelter them or cling to them, but what they need is tough love and discipline--much the same discipline that characterizes successful start-ups. R.J. Reynolds recognized that it didn't know that much about the pharmaceutical business and couldn't merely try to spin out a small clone of itself. It had to treat the venture as if it were essentially starting from scratch, with a passionate entrepreneurial leader, a solid business plan, help from outside partners in the industry, and ultimately substantial venture backing. That these lessons are less obvious to executives contemplating spinning out ventures closer to their core businesses may be why so many spinouts fail.

  1. Mechanically equivalent elastic-plastic deformations and the problem of plastic spin

    Directory of Open Access Journals (Sweden)

    Steigmann David J.

    2011-01-01

    Full Text Available The problem of plastic spin is phrased in terms of a notion of mechanical equivalence among local intermediate configurations of an elastic/ plastic crystalline solid. This idea is used to show that, without further qualification, the plastic spin may be suppressed at the constitutive level. However, the spin is closely tied to an underlying undistorted crystal lattice which, once specified, eliminates the freedom afforded by mechanical equivalence. As a practical matter a constitutive specification of plastic spin is therefore required. Suppression of plastic spin thus emerges as merely one such specification among many. Restrictions on these are derived in the case of rate-independent response.

  2. Symmetry rules for the indirect nuclear spin-spin coupling tensor revisited

    Science.gov (United States)

    Buckingham, A. D.; Pyykkö, P.; Robert, J. B.; Wiesenfeld, L.

    The symmetry rules of Buckingham and Love (1970), relating the number of independent components of the indirect spin-spin coupling tensor J to the symmetry of the nuclear sites, are shown to require modification if the two nuclei are exchanged by a symmetry operation. In that case, the anti-symmetric part of J does not transform as a second-rank polar tensor under symmetry operations that interchange the coupled nuclei and may be called an anti-tensor. New rules are derived and illustrated by simple molecular models.

  3. RHIC spin physics

    International Nuclear Information System (INIS)

    Bunce, G.

    1994-01-01

    The physics potential of colliding beams of protons, polarized either longitudinally or transversely, at RHIC is remarkable. A luminosity of L = 2 x 10 32 cm -2 with 70% polarized beams will be available with up to 250 GeV energy in each beam. The proposal to collide polarized protons in RHIC was submitted in August 1992 and approved in October 1993. We have funding for R ampersand D on Siberian Snakes, so that RHIC will be able to accelerate polarized protons early in its program. The expected date of the first heavy ion collisions is 1999. The spin physics program includes measurement of gluon and sea quark polarization in the longitudinally polarized proton, measurement and then application of parity violation in W and Z production, measurement of hard scattering parton-parton asymmetries, and quark polarization or transversity in transversely polarized protons. Single spin asymmetries allow sensitive searches for parity violation (longitudinal polarization), and correlations between quark spin and gluons (transverse). Probes include direct photons (to P T = 20 GeV/c), jets (to P T > 50 GeV/c), Drell-Yan pairs to M ell ell = 9 GeV, W ± , Z. This program is described in our Particle World paper. Here we will emphasize the new information included in our Update, given to the Brookhaven PAC this September

  4. Nuclear spin circular dichroism

    International Nuclear Information System (INIS)

    Vaara, Juha; Rizzo, Antonio; Kauczor, Joanna; Norman, Patrick; Coriani, Sonia

    2014-01-01

    Recent years have witnessed a growing interest in magneto-optic spectroscopy techniques that use nuclear magnetization as the source of the magnetic field. Here we present a formulation of magnetic circular dichroism (CD) due to magnetically polarized nuclei, nuclear spin-induced CD (NSCD), in molecules. The NSCD ellipticity and nuclear spin-induced optical rotation (NSOR) angle correspond to the real and imaginary parts, respectively, of (complex) quadratic response functions involving the dynamic second-order interaction of the electron system with the linearly polarized light beam, as well as the static magnetic hyperfine interaction. Using the complex polarization propagator framework, NSCD and NSOR signals are obtained at frequencies in the vicinity of optical excitations. Hartree-Fock and density-functional theory calculations on relatively small model systems, ethene, benzene, and 1,4-benzoquinone, demonstrate the feasibility of the method for obtaining relatively strong nuclear spin-induced ellipticity and optical rotation signals. Comparison of the proton and carbon-13 signals of ethanol reveals that these resonant phenomena facilitate chemical resolution between non-equivalent nuclei in magneto-optic spectra

  5. Rotary spin echoes

    Energy Technology Data Exchange (ETDEWEB)

    Solomon, I. [Commissariat a l' energie atomique et aux energies alternatives - CEA, Centre d' Etudes Nucleaires de Saclay, BP2, Gif-sur-Yvette (France)

    1959-07-01

    Torrey has observed the free precession of nuclear spins around an r-f field H{sub 1}, fixed in a frame rotating at the Larmor frequency ω{sub 0} = γH{sub 0} around a large d-c magnetic field H{sub 0}. He showed that for an H{sub 1}, much larger than inhomogeneity of H{sub 0}, the latter has a negligible effect on the decay of the spin magnetization which is mainly due to the inhomogeneity of H{sub 1}. We report here on a method of overcoming the inhomogeneity of H{sub 1}, by production of echoes in the rotating frame ('rotary echoes'). These echoes are obtained by a 180 deg. phase shift at t = τ on the r-f field so that H{sub 1}, is suddenly reversed, producing a re-focussing of the magnetization vectors at the time t = 2 τ. The rotary echoes so obtained are very similar to the usual spin-echoes with, however some specific features that make them particularly suitable for the measurement of long relaxation times. Reprint of a paper published in Physical Review Letters, vol. 2, no. 7, Apr 1959, p. 301-302.

  6. Rotary spin echoes

    International Nuclear Information System (INIS)

    Solomon, I.

    1959-01-01

    Torrey has observed the free precession of nuclear spins around an r-f field H 1 , fixed in a frame rotating at the Larmor frequency ω 0 = γH 0 around a large d-c magnetic field H 0 . He showed that for an H 1 , much larger than inhomogeneity of H 0 , the latter has a negligible effect on the decay of the spin magnetization which is mainly due to the inhomogeneity of H 1 . We report here on a method of overcoming the inhomogeneity of H 1 , by production of echoes in the rotating frame ('rotary echoes'). These echoes are obtained by a 180 deg. phase shift at t = τ on the r-f field so that H 1 , is suddenly reversed, producing a re-focussing of the magnetization vectors at the time t = 2 τ. The rotary echoes so obtained are very similar to the usual spin-echoes with, however some specific features that make them particularly suitable for the measurement of long relaxation times. Reprint of a paper published in Physical Review Letters, vol. 2, no. 7, Apr 1959, p. 301-302

  7. Spinning geometry = Twisted geometry

    International Nuclear Information System (INIS)

    Freidel, Laurent; Ziprick, Jonathan

    2014-01-01

    It is well known that the SU(2)-gauge invariant phase space of loop gravity can be represented in terms of twisted geometries. These are piecewise-linear-flat geometries obtained by gluing together polyhedra, but the resulting geometries are not continuous across the faces. Here we show that this phase space can also be represented by continuous, piecewise-flat three-geometries called spinning geometries. These are composed of metric-flat three-cells glued together consistently. The geometry of each cell and the manner in which they are glued is compatible with the choice of fluxes and holonomies. We first remark that the fluxes provide each edge with an angular momentum. By studying the piecewise-flat geometries which minimize edge lengths, we show that these angular momenta can be literally interpreted as the spin of the edges: the geometries of all edges are necessarily helices. We also show that the compatibility of the gluing maps with the holonomy data results in the same conclusion. This shows that a spinning geometry represents a way to glue together the three-cells of a twisted geometry to form a continuous geometry which represents a point in the loop gravity phase space. (paper)

  8. RHIC spin physics

    International Nuclear Information System (INIS)

    Bunce, G.

    1993-01-01

    The physics potential of colliding beams of protons, polarized either longitudinally or transversely, at RHIC is remarkable. A luminosity of L = 2 x 10 32 cm -2 sec -1 with 70% polarized beams will be available with up to 250 GeV energy in each beam. The proposal to collide polarized protons in RHIC was submitted in August 1992 and approved in October 1993, just after this workshop. The collaboration has been encouraged to complete R ampersand D on Siberian Snakes, so that RHIC will be able to accelerate polarized protons early in its program. The expected date of the first heavy ion collisions is 1999. The spin physics program includes measurement of gluon and sea quark polarization in the longitudinally polarized proton, measurement and then application of parity violation in W and Z production, measurement of hard scattering parton-parton asymmetries, and quark polarization or transversity in transversely polarized protons. Single spin asymmetries allow sensitive searches for parity violation (longitudinal polarization), and correlations between quark spin and gluons (transverse). Probes include direct photons (to p T = 20 GeV/c), jets (to p T > 50 GeV/c), Drell-Yan pairs (to m ll = 9 GeV), W +/- , Z. Here, the collaboration emphasizes the new information included in the Update, given to the Brookhaven PAC this September

  9. Feasibility of a spin light polarimeter at JLab

    International Nuclear Information System (INIS)

    Dutta, Dipangkar

    2011-01-01

    The future 12 GeV program at JLab includes several high precision experiments that aim to use parity violation in electroweak interactions to search for interactions beyond the Standard Model. These experiments require precision electron polarimetry with an uncertainty of ∼ 0.4%. Compton and Moller polarimeters are typically the polarimeters of choice for these experiments. However, a complimentary polarimetry technique based on the spin dependence of synchrotron radiation (SR), referred to as 'spin-light,' is often overlooked. In this article we examine the feasibility of a 'spin-light' polarimeter at Jefferson Lab (JLab) for 12 GeV experiments.

  10. Causality, spin, and equal-time commutators

    International Nuclear Information System (INIS)

    Abdel-Rahman, A.M.

    1975-01-01

    We study the causality constraints on the structure of the Lorentz-antisymmetric component of the commutator of two conserved isovector currents between fermion states of equal momenta. We discuss the sum rules that follow from causality and scaling, using the recently introduced refined infinite-momentum technique. The complete set of sum rules is found to include the spin-dependent fixed-mass sum rules obtained from light-cone commutators. The causality and scaling restrictions on the structure of the electromagnetic equal-time commutators are discussed, and it is found, in particular, that causality requires the spin-dependent part of the matrix element for the time-space electromagnetic equal-time commutator to vanish identically. It is also shown, in comparison with the electromagnetic case, that the corresponding matrix element for the time-space isovector current equal-time commutator is required, by causality, to have isospin-antisymmetric tensor and scalar operator Schwinger terms

  11. Nuclear spin noise in the central spin model

    Science.gov (United States)

    Fröhling, Nina; Anders, Frithjof B.; Glazov, Mikhail

    2018-05-01

    We study theoretically the fluctuations of the nuclear spins in quantum dots employing the central spin model which accounts for the hyperfine interaction of the nuclei with the electron spin. These fluctuations are calculated both with an analytical approach using homogeneous hyperfine couplings (box model) and with a numerical simulation using a distribution of hyperfine coupling constants. The approaches are in good agreement. The box model serves as a benchmark with low computational cost that explains the basic features of the nuclear spin noise well. We also demonstrate that the nuclear spin noise spectra comprise a two-peak structure centered at the nuclear Zeeman frequency in high magnetic fields with the shape of the spectrum controlled by the distribution of the hyperfine constants. This allows for direct access to this distribution function through nuclear spin noise spectroscopy.

  12. Entanglement entropy in random quantum spin-S chains

    International Nuclear Information System (INIS)

    Saguia, A.; Boechat, B.; Continentino, M. A.; Sarandy, M. S.

    2007-01-01

    We discuss the scaling of entanglement entropy in the random singlet phase (RSP) of disordered quantum magnetic chains of general spin S. Through an analysis of the general structure of the RSP, we show that the entanglement entropy scales logarithmically with the size of a block, and we provide a closed expression for this scaling. This result is applicable for arbitrary quantum spin chains in the RSP, being dependent only on the magnitude S of the spin. Remarkably, the logarithmic scaling holds for the disordered chain even if the pure chain with no disorder does not exhibit conformal invariance, as is the case for Heisenberg integer-spin chains. Our conclusions are supported by explicit evaluations of the entanglement entropy for random spin-1 and spin-3/2 chains using an asymptotically exact real-space renormalization group approach

  13. Spinning particle approach to higher spin field theory

    International Nuclear Information System (INIS)

    Corradini, Olindo

    2011-01-01

    We shortly review on the connection between higher-spin gauge field theories and supersymmetric spinning particle models. In such approach the higher spin equations of motion are linked to the first-class constraint algebra associated with the quantization of particle models. Here we consider a class of spinning particle models characterized by local O(N)-extended supersymmetry since these models are known to provide an alternative approach to the geometric formulation of higher spin field theory. We describe the canonical quantization of the models in curved target space and discuss the obstructions that appear in presence of an arbitrarily curved background. We then point out the special role that conformally flat spaces appear to have in such models and present a derivation of the higher-spin curvatures for maximally symmetric spaces.

  14. Spin current through quantum-dot spin valves

    International Nuclear Information System (INIS)

    Wang, J; Xing, D Y

    2006-01-01

    We report a theoretical study of the influence of the Coulomb interaction on the equilibrium spin current in a quantum-dot spin valve, in which the quantum dot described by the Anderson impurity model is coupled to two ferromagnetic leads with noncollinear magnetizations. In the Kondo regime, electrons transmit through the quantum dot via higher-order virtual processes, in which the spin of either lead electrons or a localized electron on the quantum dot may reverse. It is found that the magnitude of the spin current decreases with increasing Coulomb interactions due to spin flip effects on the dot. However, the spatial direction of the spin current remains unchanged; it is determined only by the exchange coupling between two noncollinear magnetizations

  15. Dynamical spin accumulation in large-spin magnetic molecules

    Science.gov (United States)

    Płomińska, Anna; Weymann, Ireneusz; Misiorny, Maciej

    2018-01-01

    The frequency-dependent transport through a nanodevice containing a large-spin magnetic molecule is studied theoretically in the Kondo regime. Specifically, the effect of magnetic anisotropy on dynamical spin accumulation is of primary interest. Such accumulation arises due to finite components of frequency-dependent conductance that are off diagonal in spin. Here, employing the Kubo formalism and the numerical renormalization group method, we demonstrate that the dynamical transport properties strongly depend on the relative orientation of spin moments in electrodes of the device, as well as on intrinsic parameters of the molecule. In particular, the effect of dynamical spin accumulation is found to be greatly affected by the type of magnetic anisotropy exhibited by the molecule, and it develops for frequencies corresponding to the Kondo temperature. For the parallel magnetic configuration of the device, the presence of dynamical spin accumulation is conditioned by the interplay of ferromagnetic-lead-induced exchange field and the Kondo correlations.

  16. Graphene spin diode: Strain-modulated spin rectification

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Yunhua; Wang, B., E-mail: stslyl@mail.sysu.edu.cn, E-mail: wangbiao@mail.sysu.edu.cn [Sino-French Institute of Nuclear Engineering and Technology, School of Physics and Engineering, State Key Laboratory of Optoelectronic Materials and Technologies, Sun Yat-sen University, Guangzhou 510275 (China); Liu, Yulan, E-mail: stslyl@mail.sysu.edu.cn, E-mail: wangbiao@mail.sysu.edu.cn [School of Engineering, Sun Yat-sen University, Guangzhou 510275 (China)

    2014-08-04

    Strain effects on spin transport in a ferromagnetic/strained/normal graphene junction are explored theoretically. It is shown that the spin-resolved Fermi energy range can be controlled by the armchair direction strain because the strain-induced pseudomagnetic field suppresses the current. The spin rectification effect for the bias reversal occurs because of a combination of ferromagnetic exchange splitting and the broken spatial symmetry of the junction. In addition, the spin rectification performance can be tuned remarkably by manipulation of the strains. In view of this strain-modulated spin rectification effect, we propose that the graphene-based ferromagnetic/strained/normal junction can be used as a tunable spin diode.

  17. Spin Transfer Torque in Graphene

    Science.gov (United States)

    Lin, Chia-Ching; Chen, Zhihong

    2014-03-01

    Graphene is an idea channel material for spin transport due to its long spin diffusion length. To develop graphene based spin logic, it is important to demonstrate spin transfer torque in graphene. Here, we report the experimental measurement of spin transfer torque in graphene nonlocal spin valve devices. Assisted by a small external in-plane magnetic field, the magnetization reversal of the receiving magnet is induced by pure spin diffusion currents from the injector magnet. The magnetization switching is reversible between parallel and antiparallel configurations by controlling the polarity of the applied charged currents. Current induced heating and Oersted field from the nonlocal charge flow have also been excluded in this study. Next, we further enhance the spin angular momentum absorption at the interface of the receiving magnet and graphene channel by removing the tunneling barrier in the receiving magnet. The device with a tunneling barrier only at the injector magnet shows a comparable nonlocal spin valve signal but lower electrical noise. Moreover, in the same preset condition, the critical charge current density for spin torque in the single tunneling barrier device shows a substantial reduction if compared to the double tunneling barrier device.

  18. EVENT GENERATOR FOR RHIC SPIN PHYSICS

    International Nuclear Information System (INIS)

    SAITO, N.; SCHAEFER, A.

    1999-01-01

    This volume archives the reports from the RIKEN BNL Research Center workshop on ''Event Generator for RHIC Spin Physics II'' held during the week March 15, 1999 at Brookhaven National Laboratory. It was the second meeting on the subject following a first one in last September. This workshop has been initiated to establish a firm collaboration between theorists and experimentalists involved in RHIC spin physics with the aim of developing a reliable, high-precision event generator for RHIC spin physics. Needless to say, adequate event generators are indispensable tools for high energy physics programs in general, especially in the process of: planning the experimental programs; developing algorithms to extract the physics signals of interest; estimating the background in the extracted results, and connecting the final particle kinematics to the fundamental i.e. partonic level processes. Since RHIC is the first polarized collider, dedicated efforts are required to obtain a full-fledged event generator which describes spin dependent reactions in great detail

  19. Quantum criticality among entangled spin chains

    Science.gov (United States)

    Blanc, N.; Trinh, J.; Dong, L.; Bai, X.; Aczel, A. A.; Mourigal, M.; Balents, L.; Siegrist, T.; Ramirez, A. P.

    2018-03-01

    An important challenge in magnetism is the unambiguous identification of a quantum spin liquid1,2, of potential importance for quantum computing. In such a material, the magnetic spins should be fluctuating in the quantum regime, instead of frozen in a classical long-range-ordered state. While this requirement dictates systems3,4 wherein classical order is suppressed by a frustrating lattice5, an ideal system would allow tuning of quantum fluctuations by an external parameter. Conventional three-dimensional antiferromagnets can be tuned through a quantum critical point—a region of highly fluctuating spins—by an applied magnetic field. Such systems suffer from a weak specific-heat peak at the quantum critical point, with little entropy available for quantum fluctuations6. Here we study a different type of antiferromagnet, comprised of weakly coupled antiferromagnetic spin-1/2 chains as realized in the molecular salt K2PbCu(NO2)6. Across the temperature-magnetic field boundary between three-dimensional order and the paramagnetic phase, the specific heat exhibits a large peak whose magnitude approaches a value suggestive of the spinon Sommerfeld coefficient of isolated quantum spin chains. These results demonstrate an alternative approach for producing quantum matter via a magnetic-field-induced shift of entropy from one-dimensional short-range order to a three-dimensional quantum critical point.

  20. Three-electron spin qubits

    Science.gov (United States)

    Russ, Maximilian; Burkard, Guido

    2017-10-01

    The goal of this article is to review the progress of three-electron spin qubits from their inception to the state of the art. We direct the main focus towards the exchange-only qubit (Bacon et al 2000 Phys. Rev. Lett. 85 1758-61, DiVincenzo et al 2000 Nature 408 339) and its derived versions, e.g. the resonant exchange (RX) qubit, but we also discuss other qubit implementations using three electron spins. For each three-spin qubit we describe the qubit model, the envisioned physical realization, the implementations of single-qubit operations, as well as the read-out and initialization schemes. Two-qubit gates and decoherence properties are discussed for the RX qubit and the exchange-only qubit, thereby completing the list of requirements for quantum computation for a viable candidate qubit implementation. We start by describing the full system of three electrons in a triple quantum dot, then discuss the charge-stability diagram, restricting ourselves to the relevant subsystem, introduce the qubit states, and discuss important transitions to other charge states (Russ et al 2016 Phys. Rev. B 94 165411). Introducing the various qubit implementations, we begin with the exchange-only qubit (DiVincenzo et al 2000 Nature 408 339, Laird et al 2010 Phys. Rev. B 82 075403), followed by the RX qubit (Medford et al 2013 Phys. Rev. Lett. 111 050501, Taylor et al 2013 Phys. Rev. Lett. 111 050502), the spin-charge qubit (Kyriakidis and Burkard 2007 Phys. Rev. B 75 115324), and the hybrid qubit (Shi et al 2012 Phys. Rev. Lett. 108 140503, Koh et al 2012 Phys. Rev. Lett. 109 250503, Cao et al 2016 Phys. Rev. Lett. 116 086801, Thorgrimsson et al 2016 arXiv:1611.04945). The main focus will be on the exchange-only qubit and its modification, the RX qubit, whose single-qubit operations are realized by driving the qubit at its resonant frequency in the microwave range similar to electron spin resonance. Two different types of two-qubit operations are presented for the exchange

  1. Action Potential Modulation of Neural Spin Networks Suggests Possible Role of Spin

    CERN Document Server

    Hu, H P

    2004-01-01

    In this paper we show that nuclear spin networks in neural membranes are modulated by action potentials through J-coupling, dipolar coupling and chemical shielding tensors and perturbed by microscopically strong and fluctuating internal magnetic fields produced largely by paramagnetic oxygen. We suggest that these spin networks could be involved in brain functions since said modulation inputs information carried by the neural spike trains into them, said perturbation activates various dynamics within them and the combination of the two likely produce stochastic resonance thus synchronizing said dynamics to the neural firings. Although quantum coherence is desirable and may indeed exist, it is not required for these spin networks to serve as the subatomic components for the conventional neural networks.

  2. Spin waves and spin instabilities in quantum plasmas

    OpenAIRE

    Andreev, P. A.; Kuz'menkov, L. S.

    2014-01-01

    We describe main ideas of method of many-particle quantum hydrodynamics allows to derive equations for description of quantum plasma evolution. We also present definitions of collective quantum variables suitable for quantum plasmas. We show that evolution of magnetic moments (spins) in quantum plasmas leads to several new branches of wave dispersion: spin-electromagnetic plasma waves and self-consistent spin waves. Propagation of neutron beams through quantum plasmas is also considered. Inst...

  3. Field-controlled spin current in frustrated spin chains

    Directory of Open Access Journals (Sweden)

    A.K. Kolezhuk

    2009-01-01

    Full Text Available We study states with spontaneous spin current, emerging in frustrated antiferromagnetic spin-S chains subject to a strong external magnetic field. As a numerical tool, we use a non-Abelian symmetry realization of the density matrix renormalization group. The field dependence of the order parameter and the critical exponents are presented for zigzag chains with S=1/2, 1, 3/2, and 2.

  4. Hardy's argument and successive spin-s measurements

    International Nuclear Information System (INIS)

    Ahanj, Ali

    2010-01-01

    We consider a hidden-variable theoretic description of successive measurements of noncommuting spin observables on an input spin-s state. In this scenario, the hidden-variable theory leads to a Hardy-type argument that quantum predictions violate it. We show that the maximum probability of success of Hardy's argument in quantum theory is ((1/2)) 4s , which is more than in the spatial case.

  5. Reserve valuation in electric power systems

    Science.gov (United States)

    Ruiz, Pablo Ariel

    Operational reliability is provided in part by scheduling capacity in excess of the load forecast. This reserve capacity balances the uncertain power demand with the supply in real time and provides for equipment outages. Traditionally, reserve scheduling has been ensured by enforcing reserve requirements in the operations planning. An alternate approach is to employ a stochastic formulation, which allows the explicit modeling of the sources of uncertainty. This thesis compares stochastic and reserve methods and evaluates the benefits of a combined approach for the efficient management of uncertainty in the unit commitment problem. Numerical studies show that the unit commitment solutions obtained for the combined approach are robust and superior with respect to the traditional approach. These robust solutions are especially valuable in areas with a high proportion of wind power, as their built-in flexibility allows the dispatch of practically all the available wind power while minimizing the costs of operation. The scheduled reserve has an economic value since it reduces the outage costs. In several electricity markets, reserve demand functions have been implemented to take into account the value of reserve in the market clearing process. These often take the form of a step-down function at the reserve requirement level, and as such they may not appropriately represent the reserve value. The value of reserve is impacted by the reliability, dynamic and stochastic characteristics of system components, the system operation policies, and the economic aspects such as the risk preferences of the demand. In this thesis, these aspects are taken into account to approximate the reserve value and construct reserve demand functions. Illustrative examples show that the demand functions constructed have similarities with those implemented in some markets.

  6. And the World Turned: Spin Testing the DG-1000S

    Science.gov (United States)

    2015-10-01

    mainly glass-fiber reinforced plastic, with steel as necessary for the landing gear. Load factor limits are +7/- 5g . Manufactured in Germany, the DG...Forward CG’s carry an additional type of risk for spin testing: structural failure due to over- speed /overload. After spin entry, if the aircraft’s...become “sloppy” in the DG-1000S near stall speed , careful attention to the yaw string was required for coordinated flight: anything less tended to cause

  7. QED approach to the nuclear spin-spin coupling tensor

    International Nuclear Information System (INIS)

    Romero, Rodolfo H.; Aucar, Gustavo A.

    2002-01-01

    A quantum electrodynamical approach for the calculation of the nuclear spin-spin coupling tensor of nuclear-magnetic-resonance spectroscopy is given. Quantization of radiation fields within the molecule is considered and expressions for the magnetic field in the neighborhood of a nucleus are calculated. Using a generalization of time-dependent response theory, an effective spin-spin interaction is obtained from the coupling of nuclear magnetic moments to a virtual quantized magnetic field. The energy-dependent operators obtained reduce to usual classical-field expressions at suitable limits

  8. Spin transport in spin filtering magnetic tunneling junctions.

    Science.gov (United States)

    Li, Yun; Lee, Eok Kyun

    2007-11-01

    Taking into account spin-orbit coupling and s-d interaction, we investigate spin transport properties of the magnetic tunneling junctions with spin filtering barrier using Landauer-Büttiker formalism implemented with the recursive algorithm to calculate the real-space Green function. We predict completely different bias dependence of negative tunnel magnetoresistance (TMR) between the systems composed of nonmagnetic electrode (NM)/ferromagnetic barrier (FB)/ferromagnet (FM) and NM/FB/FM/NM spin filtering tunnel junctions (SFTJs). Analyses of the results provide us possible ways of designing the systems which modulate the TMR in the negative magnetoresistance regime.

  9. Spin-orbit mediated control of spin qubits

    DEFF Research Database (Denmark)

    Flindt, Christian; Sørensen, A.S; Flensberg, Karsten

    2006-01-01

    We propose to use the spin-orbit interaction as a means to control electron spins in quantum dots, enabling both single-qubit and two-qubit operations. Very fast single-qubit operations may be achieved by temporarily displacing the electrons. For two-qubit operations the coupling mechanism is bas...... on a combination of the spin-orbit coupling and the mutual long-ranged Coulomb interaction. Compared to existing schemes using the exchange coupling, the spin-orbit induced coupling is less sensitive to random electrical fluctuations in the electrodes defining the quantum dots....

  10. Naval Petroleum and Oil Shale Reserves

    International Nuclear Information System (INIS)

    1992-01-01

    During fiscal year 1992, the reserves generated $473 million in revenues, a $181 million decrease from the fiscal year 1991 revenues, primarily due to significant decreases in oil and natural gas prices. Total costs were $200 million, resulting in net cash flow of $273 million, compared with $454 million in fiscal year 1991. From 1976 through fiscal year 1992, the Naval Petroleum and Oil Shale Reserves generated more than $15 billion in revenues and a net operating income after costs of $12.5 billion. In fiscal year 1992, production at the Naval Petroleum Reserves at maximum efficient rates yielded 26 million barrels of crude oil, 119 billion cubic feet of natural gas, and 164 million gallons of natural gas liquids. From April to November 1992, senior managers from the Naval Petroleum and Oil Shale Reserves held a series of three workshops in Boulder, Colorado, in order to build a comprehensive Strategic Plan as required by Secretary of Energy Notice 25A-91. Other highlights are presented for the following: Naval Petroleum Reserve No. 1--production achievements, crude oil shipments to the strategic petroleum reserve, horizontal drilling, shallow oil zone gas injection project, environment and safety, and vanpool program; Naval Petroleum Reserve No. 2--new management and operating contractor and exploration drilling; Naval Petroleum Reserve No. 3--steamflood; Naval Oil Shale Reserves--protection program; and Tiger Team environmental assessment of the Naval Petroleum and Oil Shale Reserves in Colorado, Utah, and Wyoming

  11. Wind Farms’ Spatial Distribution Effect on Power System Reserves Requirements

    DEFF Research Database (Denmark)

    Sørensen, Poul Ejnar; Cutululis, Nicolaos Antonio

    2010-01-01

    The wind power development during last millennium was typically based on small wind turbines dispersed over large areas, leading to a significant smoothing of the wind power fluctuations in a power system balancing area. The present development goes towards much larger wind farms, concentrated...

  12. Classification and quantification of reserve requirements for balancing

    NARCIS (Netherlands)

    Frunt, J.; Kling, W.L.; Bosch, van den P.P.J.

    2010-01-01

    In electrical power systems there must always be a balance between supply and demand of power. Any imbalance will result in a frequency deviation. To reduce the imbalance to zero, ancillary services for balance management are in use. Ancillary services for balance management are characterized by

  13. Defense Inventory: Army War Reserve Spare Parts Requirements Are Uncertain

    National Research Council Canada - National Science Library

    2001-01-01

    .... Department of Defense policy calls for each of the services to acquire and maintain sufficient war materiel inventories to commence execution of the two-war scenario and sustain operations until...

  14. ac spin-Hall effect

    International Nuclear Information System (INIS)

    Entin-Wohlman, O.

    2005-01-01

    Full Text:The spin-Hall effect is described. The Rashba and Dresselhaus spin-orbit interactions are both shown to yield the low temperature spin-Hall effect for strongly localized electrons coupled to phonons. A frequency-dependent electric field E(ω) generates a spin-polarization current, normal to E, due to interference of hopping paths. At zero temperature the corresponding spin-Hall conductivity is real and is proportional to ω 2 . At non-zero temperatures the coupling to the phonons yields an imaginary term proportional to ω. The interference also yields persistent spin currents at thermal equilibrium, at E = 0. The contributions from the Dresselhaus and Rashba interactions to the interference oppose each other

  15. Spin Polarization Oscillations without Spin Precession: Spin-Orbit Entangled Resonances in Quasi-One-Dimensional Spin Transport

    Directory of Open Access Journals (Sweden)

    D. H. Berman

    2014-03-01

    Full Text Available Resonant behavior involving spin-orbit entangled states occurs for spin transport along a narrow channel defined in a two-dimensional electron gas, including an apparent rapid relaxation of the spin polarization for special values of the channel width and applied magnetic field (so-called ballistic spin resonance. A fully quantum-mechanical theory for transport using multiple subbands of the one-dimensional system provides the dependence of the spin density on the applied magnetic field and channel width and position along the channel. We show how the spatially nonoscillating part of the spin density vanishes when the Zeeman energy matches the subband energy splittings. The resonance phenomenon persists in the presence of disorder.

  16. Sensitivity enhancement by multiple-contact cross-polarization under magic-angle spinning.

    Science.gov (United States)

    Raya, J; Hirschinger, J

    2017-08-01

    Multiple-contact cross-polarization (MC-CP) is applied to powder samples of ferrocene and l-alanine under magic-angle spinning (MAS) conditions. The method is described analytically through the density matrix formalism. The combination of a two-step memory function approach and the Anderson-Weiss approximation is found to be particularly useful to derive approximate analytical solutions for single-contact Hartmann-Hahn CP (HHCP) and MC-CP dynamics under MAS. We show that the MC-CP sequence requiring no pulse-shape optimization yields higher polarizations at short contact times than optimized adiabatic passage through the HH condition CP (APHH-CP) when the MAS frequency is comparable to the heteronuclear dipolar coupling, i.e., when APHH-CP through a single sideband matching condition is impossible or difficult to perform. It is also shown that the MC-CP sideband HH conditions are generally much broader than for single-contact HHCP and that efficient polarization transfer at the centerband HH condition can be reintroduced by rotor-asynchronous multiple equilibrations-re-equilibrations with the proton spin bath. Boundary conditions for the successful use of the MC-CP experiment when relying on spin-lattice relaxation for repolarization are also examined. Copyright © 2017 Elsevier Inc. All rights reserved.

  17. Latent dimensions of social anxiety disorder: A re-evaluation of the Social Phobia Inventory (SPIN).

    Science.gov (United States)

    Campbell-Sills, Laura; Espejo, Emmanuel; Ayers, Catherine R; Roy-Byrne, Peter; Stein, Murray B

    2015-12-01

    The Social Phobia Inventory (SPIN; Connor et al., 2000) is a well-validated instrument for assessing severity of social anxiety disorder (SAD). However, evaluations of its factor structure have produced inconsistent results and this aspect of the scale requires further study. Primary care patients with SAD (N=397) completed the SPIN as part of baseline assessment for the Coordinated Anxiety Learning and Management study (Roy-Byrne et al., 2010). These data were used for exploratory and confirmatory factor analysis of the SPIN. A 3-factor model provided the best fit for the data and factors were interpreted as Fear of Negative Evaluation, Fear of Physical Symptoms, and Fear of Uncertainty in Social Situations. Tests of a second-order model showed that the three factors loaded strongly on a single higher-order factor that was labeled Social Anxiety. Findings are consistent with theories identifying Fear of Negative Evaluation as the core feature of SAD, and with evidence that anxiety sensitivity and intolerance of uncertainty further contribute to SAD severity. Copyright © 2015 Elsevier Ltd. All rights reserved.

  18. Asymptotics of relativistic spin networks

    International Nuclear Information System (INIS)

    Barrett, John W; Steele, Christopher M

    2003-01-01

    The stationary phase technique is used to calculate asymptotic formulae for SO(4) relativistic spin networks. For the tetrahedral spin network this gives the square of the Ponzano-Regge asymptotic formula for the SU(2) 6j-symbol. For the 4-simplex (10j-symbol) the asymptotic formula is compared with numerical calculations of the spin network evaluation. Finally, we discuss the asymptotics of the SO(3, 1) 10j-symbol

  19. Nuclear spin conversion in formaldehyde

    OpenAIRE

    Chapovsky, Pavel L.

    2000-01-01

    Theoretical model of the nuclear spin conversion in formaldehyde (H2CO) has been developed. The conversion is governed by the intramolecular spin-rotation mixing of molecular ortho and para states. The rate of conversion has been found equal 1.4*10^{-4}~1/s*Torr. Temperature dependence of the spin conversion has been predicted to be weak in the wide temperature range T=200-900 K.

  20. Spin interactions of light quarks

    International Nuclear Information System (INIS)

    Simonov, Yu.A.

    1989-01-01

    Spin-spin and spin-orbit interactions of light quarks is calculated exactly, i.e. without use of perturbation expansion in (mass) -1 . Vacuum gluonic fields are represented by bilocal correlators and higher order correlators are neglected. Perturbative contribution is reproduced in lowest order by a simple modification of the bilocal correlator, and the smearing of the function in the hyperfine term is discussed. 12 refs

  1. Calculation of spin-densities within the context of density functional theory. The crucial role of the correlation functional

    NARCIS (Netherlands)

    Filatov, M; Cremer, D

    2005-01-01

    It is demonstrated that the LYP correlation functional is not suited to be used for the calculation of electron spin resonance hyperfine structure (HFS) constants, nuclear magnetic resonance spin-spin coupling constants, magnetic, shieldings and other properties that require a balanced account of

  2. Observation of the spin Nernst effect

    Science.gov (United States)

    Meyer, S.; Chen, Y.-T.; Wimmer, S.; Althammer, M.; Wimmer, T.; Schlitz, R.; Geprägs, S.; Huebl, H.; Ködderitzsch, D.; Ebert, H.; Bauer, G. E. W.; Gross, R.; Goennenwein, S. T. B.

    2017-10-01

    The observation of the spin Hall effect triggered intense research on pure spin current transport. With the spin Hall effect, the spin Seebeck effect and the spin Peltier effect already observed, our picture of pure spin current transport is almost complete. The only missing piece is the spin Nernst (-Ettingshausen) effect, which so far has been discussed only on theoretical grounds. Here, we report the observation of the spin Nernst effect. By applying a longitudinal temperature gradient, we generate a pure transverse spin current in a Pt thin film. For readout, we exploit the magnetization-orientation-dependent spin transfer to an adjacent yttrium iron garnet layer, converting the spin Nernst current in Pt into a controlled change of the longitudinal and transverse thermopower voltage. Our experiments show that the spin Nernst and the spin Hall effect in Pt are of comparable magnitude, but differ in sign, as corroborated by first-principles calculations.

  3. RHIC spin program

    International Nuclear Information System (INIS)

    Bunce, G.

    1995-01-01

    Colliding beams of high energy polarized protons at RHIC is an excellent way to probe the polarization of gluons, u and d quarks in a polarized proton. RHIC is the Relativistic Heavy Ion Collider being built now at Brookhaven in the ISABELLE tunnel. It is designed to collide gold ions on gold ions at 100 GeV/nucleon. Its goal is to discover the quark-gluon plasma, and the first collisions are expected in March, 1999. RHIC will also make an ideal polarized proton collider with high luminosity and 250 GeV x 250 GeV collisions. The RHIC spin physics program is: (1) Use well-understood perturbative QCD probes to study non-perturbative confining dynamics in QCD. We will measure - gluon and sea quark polarization in a polarized proton, polarization of quarks in a transversely polarized proton. (2) Look for additional surprises using the first high energy polarized proton collider. We will - look for the expected maximal parity violation in W and Z boson production, - search for parity violation in other processes, - test parton models with spin. This lecture is organized around a few of the key ideas: Siberian Snakes--What are they? High energy proton-proton collisions are scatters of quarks and leptons, at high x, a polarized proton beam is a beam of polarized u quarks, quark and gluon collisions are very sensitive to spin. We will discuss two reactions: how direct photon production measures gluon polarization, and how W + boson production measures u and d quark polarization

  4. RHIC spin program

    Energy Technology Data Exchange (ETDEWEB)

    Bunce, G.

    1995-12-31

    Colliding beams of high energy polarized protons at RHIC is an excellent way to probe the polarization of gluons, u and d quarks in a polarized proton. RHIC is the Relativistic Heavy Ion Collider being built now at Brookhaven in the ISABELLE tunnel. It is designed to collide gold ions on gold ions at 100 GeV/nucleon. Its goal is to discover the quark-gluon plasma, and the first collisions are expected in March, 1999. RHIC will also make an ideal polarized proton collider with high luminosity and 250 GeV x 250 GeV collisions. The RHIC spin physics program is: (1) Use well-understood perturbative QCD probes to study non-perturbative confining dynamics in QCD. We will measure - gluon and sea quark polarization in a polarized proton, polarization of quarks in a transversely polarized proton. (2) Look for additional surprises using the first high energy polarized proton collider. We will - look for the expected maximal parity violation in W and Z boson production, - search for parity violation in other processes, - test parton models with spin. This lecture is organized around a few of the key ideas: Siberian Snakes--What are they? High energy proton-proton collisions are scatters of quarks and leptons, at high x, a polarized proton beam is a beam of polarized u quarks, quark and gluon collisions are very sensitive to spin. We will discuss two reactions: how direct photon production measures gluon polarization, and how W{sup +} boson production measures u and d quark polarization.

  5. Phenomena at very high spins

    International Nuclear Information System (INIS)

    Stephens, F.S.

    1980-03-01

    The present talk has three parts: first, a discussion of current ideas about the physics of very high spin states; second, some comments about noncollective behavior up to the highest spins where it is known, approx. 40 h; and finally, a presentation of the newest method for studying collective behavior up to spins of 60 to 70 h. The intention is that the overview presented in the first part will be sufficiently broad to indicate the relationship of the noncollective and collective behavior discussed in the other parts, and to provide some understanding of the compromise in behavior that seems to occur at the very highest spins. 13 figures

  6. Spin correlations in quantum wires

    Science.gov (United States)

    Sun, Chen; Pokrovsky, Valery L.

    2015-04-01

    We consider theoretically spin correlations in a one-dimensional quantum wire with Rashba-Dresselhaus spin-orbit interaction (RDI). The correlations of noninteracting electrons display electron spin resonance at a frequency proportional to the RDI coupling. Interacting electrons, upon varying the direction of the external magnetic field, transit from the state of Luttinger liquid (LL) to the spin-density wave (SDW) state. We show that the two-time total-spin correlations of these states are significantly different. In the LL, the projection of total spin to the direction of the RDI-induced field is conserved and the corresponding correlator is equal to zero. The correlators of two components perpendicular to the RDI field display a sharp electron-spin resonance driven by the RDI-induced intrinsic field. In contrast, in the SDW state, the longitudinal projection of spin dominates, whereas the transverse components are suppressed. This prediction indicates a simple way for an experimental diagnostic of the SDW in a quantum wire. We point out that the Luttinger model does not respect the spin conservation since it assumes the infinite Fermi sea. We propose a proper cutoff to correct this failure.

  7. Towards spin injection into silicon

    Energy Technology Data Exchange (ETDEWEB)

    Dash, S.P.

    2007-08-15

    Si has been studied for the purpose of spin injection extensively in this thesis. Three different concepts for spin injection into Si have been addressed: (1) spin injection through a ferromagnet-Si Schottky contact, (2) spin injection using MgO tunnel barriers in between the ferromagnet and Si, and (3) spin injection from Mn-doped Si (DMS) as spin aligner. (1) FM-Si Schottky contact for spin injection: To be able to improve the interface qualities one needs to understand the atomic processes involved in the formation of silicide phases. In order to obtain more detailed insight into the formation of such phases the initial stages of growth of Co and Fe were studied in situ by HRBS with monolayer depth resolution.(2) MgO tunnel barrier for spin injection into Si: The fabrication and characterization of ultra-thin crystalline MgO tunnel barriers on Si (100) was presented. (3) Mn doped Si for spin injection: Si-based diluted magnetic semiconductor samples were prepared by doping Si with Mn by two different methods i) by Mn ion implantation and ii) by in-diffusion of Mn atoms (solid state growth). (orig.)

  8. The straintronic spin-neuron

    International Nuclear Information System (INIS)

    Biswas, Ayan K; Bandyopadhyay, Supriyo; Atulasimha, Jayasimha

    2015-01-01

    In artificial neural networks, neurons are usually implemented with highly dissipative CMOS-based operational amplifiers. A more energy-efficient implementation is a ‘spin-neuron’ realized with a magneto-tunneling junction (MTJ) that is switched with a spin-polarized current (representing weighted sum of input currents) that either delivers a spin transfer torque or induces domain wall motion in the soft layer of the MTJ to mimic neuron firing. Here, we propose and analyze a different type of spin-neuron in which the soft layer of the MTJ is switched with mechanical strain generated by a voltage (representing weighted sum of input voltages) and term it straintronic spin-neuron. It dissipates orders of magnitude less energy in threshold operations than the traditional current-driven spin neuron at 0 K temperature and may even be faster. We have also studied the room-temperature firing behaviors of both types of spin neurons and find that thermal noise degrades the performance of both types, but the current-driven type is degraded much more than the straintronic type if both are optimized for maximum energy-efficiency. On the other hand, if both are designed to have the same level of thermal degradation, then the current-driven version will dissipate orders of magnitude more energy than the straintronic version. Thus, the straintronic spin-neuron is superior to current-driven spin neurons. (paper)

  9. Nuclear spin states and quantum logical operations

    International Nuclear Information System (INIS)

    Orlova, T.A.; Rasulov, E.N.

    2006-01-01

    Full text: To build a really functional quantum computer, researchers need to develop logical controllers known as 'gates' to control the state of q-bits. In this work , equal quantum logical operations are examined with the emphasis on 1-, 2-, and 3-q-bit gates.1-q-bit quantum logical operations result in Boolean 'NOT'; the 'NOT' and '√NOT' operations are described from the classical and quantum perspective. For the 'NOT' operation to be performed, there must be a means to switch the state of q-bits from to and vice versa. For this purpose either a light or radio pulse of a certain frequency can be used. If the nucleus has the spin-down state, the spin will absorb a portion of energy from electromagnetic current and switch into the spin-up state, and the radio pulse will force it to switch into state. An operation thus described from purely classical perspective is clearly understood. However, operations not analogous to the classical type may also be performed. If the above mentioned radio pulses are only half the frequency required to cause a state switch in the nuclear spin, the nuclear spin will enter the quantum superposition state of the ground state (↓) and excited states (↑). A recurring radio pulse will then result in an operation equivalent to 'NOT', for which reason the described operation is called '√NOT'. Such an operation allows for the state of quantum superposition in quantum computing, which enables parallel processing of several numbers. The work also treats the principles of 2-q-bit logical operations of the controlled 'NOT' type (CNOT), 2-q-bit (SWAP), and the 3-q-bit 'TAFFOLI' gate. (author)

  10. Transverse spin physics

    CERN Document Server

    Barone, Vicenzo

    2001-01-01

    This book is devoted to the theory and phenomenology of transverse-spin effects in high-energy hadronic physics. Contrary to common past belief, it is now rather clear that such effects are far from irrelevant. A decade or so of intense theoretical work has shed much light on the subject and brought to surface an entire class of new phenomena, which now await thorough experimental investigation. Over the next few years a number of experiments world-wide (at BNL, CERN, DESY and JLAB) will run with transversely polarised beams and targets, providing data that will enrich our knowledge of the tra

  11. Electron spin resonance

    International Nuclear Information System (INIS)

    Wasson, J.R.; Salinas, J.E.

    1980-01-01

    Published literature concerning electron spin resonance (ESR) from July 1977 to July 1979 is reviewed. The 108 literature sources cited were chosen from literally thousands and are intended to serve as a guide to the current literature and to provide an eclectic selection of publications cited for their contributions to the advance and/or applications of ESR spectroscopy. 40 of the sources are reviews, and a table is included to indicate the topic(s) mainly covered in each review. Other divisions of the material reviewed are apparatus and spectral analysis, analytical applications, and selected paramagnetic materials

  12. Status of fossil fuel reserves

    International Nuclear Information System (INIS)

    Laherrere, J.

    2005-01-01

    Reserves represent the sum of past and future productions up to the end of production. In most countries the reserve data of fields are confidential. Therefore, fossil fuel reserves are badly known because the published data are more political than technical and many countries make a confusion between resources and reserves. The cumulated production of fossil fuels represents only between a third and a fifth of the ultimate reserves. The production peak will take place between 2020 and 2050. In the ultimate reserves, which extrapolate the past, the fossil fuels represent three thirds of the overall energy. This document analyses the uncertainties linked with fossil fuel reserves: reliability of published data, modeling of future production, comparison with other energy sources, energy consumption forecasts, reserves/production ratio, exploitation of non-conventional hydrocarbons (tar sands, extra-heavy oils, bituminous shales, coal gas, gas shales, methane in overpressure aquifers, methane hydrates), technology impacts, prices impact, and reserves growth. (J.S.)

  13. Perspectives of using spin waves for computing and signal processing

    Energy Technology Data Exchange (ETDEWEB)

    Csaba, György, E-mail: gcsaba@gmail.com [Center for Nano Science and Technology, University of Notre Dame (United States); Faculty for Information Technology and Bionics, Pázmány Péter Catholic University (Hungary); Papp, Ádám [Center for Nano Science and Technology, University of Notre Dame (United States); Faculty for Information Technology and Bionics, Pázmány Péter Catholic University (Hungary); Porod, Wolfgang [Center for Nano Science and Technology, University of Notre Dame (United States)

    2017-05-03

    Highlights: • We give an overview of spin wave-based computing with emphasis on non-Boolean signal processors. • Spin waves can combine the best of electronics and photonics and do it in an on-chip and integrable way. • Copying successful approaches from microelectronics may not be the best way toward spin-wave based computing. • Practical devices can be constructed by minimizing the number of required magneto-electric interconnections. - Abstract: Almost all the world's information is processed and transmitted by either electric currents or photons. Now they may get a serious contender: spin-wave-based devices may just perform some information-processing tasks in a lot more efficient and practical way. In this article, we give an engineering perspective of the potential of spin-wave-based devices. After reviewing various flavors for spin-wave-based processing devices, we argue that the niche for spin-wave-based devices is low-power, compact and high-speed signal-processing devices, where most traditional electronics show poor performance.

  14. The Pauli equation with differential operators for the spin

    International Nuclear Information System (INIS)

    Kern, E.

    1978-01-01

    The spin operator s = (h/2) sigma in the Pauli equation fulfills the commutation relation of the angular momentum and leads to half-integer eigenvalues of the eigenfunctions for s. If one tries to express s by canonically conjugated operators PHI and π = ( /i)delta/deltaPHI the formal angular momentum term s = PHIxπ fails because it leads only to whole-integer eigenvalues. However, the modification of this term in the form s = 1/2(π+PHI(PHI π)+PHIxπ) leads to the required result. The eigenfunction system belonging to this differential operator s(PHI, π) consists of (2s + 1) spin eigenfunctions xim(PHI) which are given explicitly. They form a basis for the wave functions of a particle of spin s. Applying this formalism to particles with s = 1/2, agreement is reached with Pauli's spin theory. The function s(PHI, π) follows from the theory of rotating rigid bodies. The continuous spin-variable PHI = ( x, y, z) can be interpreted classically as a 'turning vector' which defines the orientation in space of a rigid body. PHI is the positioning coordinate of the rigid body or the spin coordinate of the particle in analogy to the cartesian coordinate x. The spin s is a vector fixed to the body. (orig.) [de

  15. Time Frequency Analysis of Spacecraft Propellant Tank Spinning Slosh

    Science.gov (United States)

    Green, Steven T.; Burkey, Russell C.; Sudermann, James

    2010-01-01

    Many spacecraft are designed to spin about an axis along the flight path as a means of stabilizing the attitude of the spacecraft via gyroscopic stiffness. Because of the assembly requirements of the spacecraft and the launch vehicle, these spacecraft often spin about an axis corresponding to a minor moment of inertia. In such a case, any perturbation of the spin axis will cause sloshing motions in the liquid propellant tanks that will eventually dissipate enough kinetic energy to cause the spin axis nutation (wobble) to grow further. This spinning slosh and resultant nutation growth is a primary design problem of spinning spacecraft and one that is not easily solved by analysis or simulation only. Testing remains the surest way to address spacecraft nutation growth. This paper describes a test method and data analysis technique that reveal the resonant frequency and damping behavior of liquid motions in a spinning tank. Slosh resonant frequency and damping characteristics are necessary inputs to any accurate numerical dynamic simulation of the spacecraft.

  16. Feedback-tuned, noise resilient gates for encoded spin qubits

    Science.gov (United States)

    Bluhm, Hendrik

    Spin 1/2 particles form native two level systems and thus lend themselves as a natural qubit implementation. However, encoding a single qubit in several spins entails benefits, such as reducing the resources necessary for qubit control and protection from certain decoherence channels. While several varieties of such encoded spin qubits have been implemented, accurate control remains challenging, and leakage out of the subspace of valid qubit states is a potential issue. Optimal performance typically requires large pulse amplitudes for fast control, which is prone to systematic errors and prohibits standard control approaches based on Rabi flopping. Furthermore, the exchange interaction typically used to electrically manipulate encoded spin qubits is inherently sensitive to charge noise. I will discuss all-electrical, high-fidelity single qubit operations for a spin qubit encoded in two electrons in a GaAs double quantum dot. Starting from a set of numerically optimized control pulses, we employ an iterative tuning procedure based on measured error syndromes to remove systematic errors.Randomized benchmarking yields an average gate fidelity exceeding 98 % and a leakage rate into invalid states of 0.2 %. These gates exhibit a certain degree of resilience to both slow charge and nuclear spin fluctuations due to dynamical correction analogous to a spin echo. Furthermore, the numerical optimization minimizes the impact of fast charge noise. Both types of noise make relevant contributions to gate errors. The general approach is also adaptable to other qubit encodings and exchange based two-qubit gates.

  17. Determination of the Pt spin diffusion length by spin-pumping and spin Hall effect

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Wei; Pearson, John E.; Hoffmann, Axel [Materials Science Division, Argonne National Laboratory, Argonne, Illinois 60439 (United States); Vlaminck, Vincent [Materials Science Division, Argonne National Laboratory, Argonne, Illinois 60439 (United States); Colegio de Ciencias e Ingenería, Universidad San Fransciso de Quito, Quito (Ecuador); Divan, Ralu [Center for Nanoscale Materials, Argonne National Laboratory, Illinois 60439 (United States); Bader, Samuel D. [Materials Science Division, Argonne National Laboratory, Argonne, Illinois 60439 (United States); Center for Nanoscale Materials, Argonne National Laboratory, Illinois 60439 (United States)

    2013-12-09

    The spin diffusion length of Pt at room temperature and at 8 K is experimentally determined via spin pumping and spin Hall effect in permalloy/Pt bilayers. Voltages generated during excitation of ferromagnetic resonance from the inverse spin Hall effect and anisotropic magnetoresistance effect were investigated with a broadband approach. Varying the Pt layer thickness gives rise to an evolution of the voltage line shape due to the superposition of the above two effects. By studying the ratio of the two voltage components with the Pt layer thickness, the spin diffusion length of Pt can be directly extracted. We obtain a spin diffusion length of ∼1.2 nm at room temperature and ∼1.6 nm at 8 K.

  18. Angular dependence of spin-orbit spin-transfer torques

    KAUST Repository

    Lee, Ki-Seung

    2015-04-06

    In ferromagnet/heavy-metal bilayers, an in-plane current gives rise to spin-orbit spin-transfer torque, which is usually decomposed into fieldlike and dampinglike torques. For two-dimensional free-electron and tight-binding models with Rashba spin-orbit coupling, the fieldlike torque acquires nontrivial dependence on the magnetization direction when the Rashba spin-orbit coupling becomes comparable to the exchange interaction. This nontrivial angular dependence of the fieldlike torque is related to the Fermi surface distortion, determined by the ratio of the Rashba spin-orbit coupling to the exchange interaction. On the other hand, the dampinglike torque acquires nontrivial angular dependence when the Rashba spin-orbit coupling is comparable to or stronger than the exchange interaction. It is related to the combined effects of the Fermi surface distortion and the Fermi sea contribution. The angular dependence is consistent with experimental observations and can be important to understand magnetization dynamics induced by spin-orbit spin-transfer torques.

  19. Spin motive forces, 'measurements', and spin-valves

    International Nuclear Information System (INIS)

    Barnes, S.E.

    2007-01-01

    Discussed is the spin motive force (smf) produced by a spin valve, this reflecting its dynamics. Relaxation implies an implicit measurement of the magnetization of the free layer of a valve. It is shown this has implications for the angular dependence of the torque transfer. Some discussion of recent experiments is included

  20. Spin energy levels in axial symmetry: spin 4

    Energy Technology Data Exchange (ETDEWEB)

    de Biasi, R S; Portella, P D [Instituto Militar de Engenharia, Rio de Janeiro (Brazil). Secao de Engenharia e Ciencia dos Materiais

    1979-01-01

    The spin energy levels in axial symmetry are presented, in graphical and tabular form, for a spin 4. The levels are calculated for five different angles between the applied field and the symmetry axis 0/sup 0/, 30/sup 0/, 45/sup 0/, 60 and 90/sup 0/.

  1. Spin energy levels in axial symmetry: spin 3/2

    Energy Technology Data Exchange (ETDEWEB)

    de Biasi, R S; Portella, P D [Instituto Militar de Engenharia, Rio de Janeiro (Brazil). Secao de Engenharia e Ciencia dos Materiais

    1977-01-01

    The spin energy levels in axial symmetry are presented, in graphical and tabular form, for a spin 3/2. The levels are calculated for five different angles between the applied field and the symmetry axis: 0/sup 0/, 30/sup 0/, 45/sup 0/, 60/sup 0/ and 90/sup 0/.

  2. Angular dependence of spin-orbit spin-transfer torques

    KAUST Repository

    Lee, Ki-Seung; Go, Dongwook; Manchon, Aurelien; Haney, Paul M.; Stiles, M. D.; Lee, Hyun-Woo; Lee, Kyung-Jin

    2015-01-01

    In ferromagnet/heavy-metal bilayers, an in-plane current gives rise to spin-orbit spin-transfer torque, which is usually decomposed into fieldlike and dampinglike torques. For two-dimensional free-electron and tight-binding models with Rashba spin-orbit coupling, the fieldlike torque acquires nontrivial dependence on the magnetization direction when the Rashba spin-orbit coupling becomes comparable to the exchange interaction. This nontrivial angular dependence of the fieldlike torque is related to the Fermi surface distortion, determined by the ratio of the Rashba spin-orbit coupling to the exchange interaction. On the other hand, the dampinglike torque acquires nontrivial angular dependence when the Rashba spin-orbit coupling is comparable to or stronger than the exchange interaction. It is related to the combined effects of the Fermi surface distortion and the Fermi sea contribution. The angular dependence is consistent with experimental observations and can be important to understand magnetization dynamics induced by spin-orbit spin-transfer torques.

  3. Diffusion equation and spin drag in spin-polarized transport

    DEFF Research Database (Denmark)

    Flensberg, Karsten; Jensen, Thomas Stibius; Mortensen, Asger

    2001-01-01

    We study the role of electron-electron interactions for spin-polarized transport using the Boltzmann equation, and derive a set of coupled transport equations. For spin-polarized transport the electron-electron interactions are important, because they tend to equilibrate the momentum of the two-s...

  4. Complete snake and rotator schemes for spin polarization in proton rings and large electron rings

    International Nuclear Information System (INIS)

    Steffen, K.

    1983-11-01

    In order to maintain spin polarization in proton rings and large electron rings, some generalized Siberian Snake scheme may be required to make the spin tune almost independent of energy and thus avoid depolarizing resonances. The practical problem of finding such schemes that, at reasonable technical effort, can be made to work over large energy ranges has been addressed before and is here revisited in a broadened view and with added new suggestions. As a result, possibly optimum schemes for electron rings (LEP) and proton rings are described. In the proposed LEP scheme, spin rotation is devised such that, at the interaction points, the spin direction is longitudinal as required for experiments. (orig.)

  5. Spin caloritronics, origin and outlook

    International Nuclear Information System (INIS)

    Yu, Haiming; Brechet, Sylvain D.; Ansermet, Jean-Philippe

    2017-01-01

    Spin caloritronics refers to research efforts in spintronics when a heat current plays a role. In this review, we start out by reviewing the predictions that can be drawn from the thermodynamics of irreversible processes. This serves as a conceptual framework in which to analyze the interplay of charge, spin and heat transport. This formalism predicts tensorial relations between vectorial quantities such as currents and gradients of chemical potentials or of temperature. Transverse effects such as the Nernst or Hall effects are predicted on the basis that these tensors can include an anti-symmetric contribution, which can be written with a vectorial cross-product. The local symmetry of the system may determine the direction of the vector defining such transverse effects, such as the surface of an isotropic medium. By including magnetization as state field in the thermodynamic description, spin currents appear naturally from the continuity equation for the magnetization, and dissipative spin torques are derived, which are charge-driven or heat-driven. Thermodynamics does not give the strength of these effects, but may provide relationships between them. Based on this framework, the review proceeds by showing how these effects have been observed in various systems. Spintronics has become a vast field of research, and the experiments highlighted in this review pertain only to heat effects on transport and magnetization dynamics, such as magneto-thermoelectric power, or the spin-dependence of the Seebeck effect, the spin-dependence of the Peltier effect, the spin Seebeck effect, the magnetic Seebeck effect, or the Nernst effect. The review concludes by pointing out predicted effects that are yet to be verified experimentally, and in what novel materials the standard thermal spin effects could be investigated. - Highlights: • Thermodynamic description of transport: three-current model. • Magneto-thermoelectric power and spin-dependent Peltier effects. • Thermal

  6. Semiconductors put spin in spintronics

    International Nuclear Information System (INIS)

    Weiss, Dieter

    2000-01-01

    Electrons and holes, which carry the current in semiconductor devices, are quantum-mechanical objects characterized by a set of quantum numbers - the band index, the wave-vector (which is closely related to the electron or hole velocity) and spin. The spin, however, is one of the strangest properties of particles. In simple terms, we can think of the spin as an internal rotation of the electron, but it has no classical counterpart. The spin is connected to a quantized magnetic moment and hence acts as a microscopic magnet. Thus the electron spin can adopt one of two directions (''up'' or ''down'') in a magnetic field. The spin plays no role in conventional electronics and the current in any semiconductor device is made up of a mixture of electrons with randomly oriented spins. However, a new range of electronic devices that transport the spin of the electrons, in addition to their charge, is being developed. But the biggest obstacle to making practical ''spin electronic'' or ''spintronic'' devices so far has been finding a way of injecting spin-polarized electrons or holes into the semiconductor and then detecting them. Recently a team of physicists from the University of Wuerzburg in Germany, and also a collaboration of researchers from Tohoku University in Japan and the University of California at Santa Barbara, have found a way round these problems using either semi-magnetic or ferromagnetic semiconductors as ''spin aligners'' (R Fiederling et al. 1999 Nature 402 787; Y Ohno et al. 1999 Nature 402 790). In this article the author presents the latest breakthrough in spintronics research. (UK)

  7. Spin caloritronics, origin and outlook

    Energy Technology Data Exchange (ETDEWEB)

    Yu, Haiming, E-mail: haiming.yu@buaa.edu.cn [Fert Beijing Institute, School of Electronic and Information Engineering, BDBC, Beihang University (China); Brechet, Sylvain D. [Institute of Physics, station 3, Ecole Polytechnique Fédérale de Lausanne, 1015 Lausanne-EPFL (Switzerland); Ansermet, Jean-Philippe, E-mail: jean-philippe.ansermet@epfl.ch [Institute of Physics, station 3, Ecole Polytechnique Fédérale de Lausanne, 1015 Lausanne-EPFL (Switzerland)

    2017-03-03

    Spin caloritronics refers to research efforts in spintronics when a heat current plays a role. In this review, we start out by reviewing the predictions that can be drawn from the thermodynamics of irreversible processes. This serves as a conceptual framework in which to analyze the interplay of charge, spin and heat transport. This formalism predicts tensorial relations between vectorial quantities such as currents and gradients of chemical potentials or of temperature. Transverse effects such as the Nernst or Hall effects are predicted on the basis that these tensors can include an anti-symmetric contribution, which can be written with a vectorial cross-product. The local symmetry of the system may determine the direction of the vector defining such transverse effects, such as the surface of an isotropic medium. By including magnetization as state field in the thermodynamic description, spin currents appear naturally from the continuity equation for the magnetization, and dissipative spin torques are derived, which are charge-driven or heat-driven. Thermodynamics does not give the strength of these effects, but may provide relationships between them. Based on this framework, the review proceeds by showing how these effects have been observed in various systems. Spintronics has become a vast field of research, and the experiments highlighted in this review pertain only to heat effects on transport and magnetization dynamics, such as magneto-thermoelectric power, or the spin-dependence of the Seebeck effect, the spin-dependence of the Peltier effect, the spin Seebeck effect, the magnetic Seebeck effect, or the Nernst effect. The review concludes by pointing out predicted effects that are yet to be verified experimentally, and in what novel materials the standard thermal spin effects could be investigated. - Highlights: • Thermodynamic description of transport: three-current model. • Magneto-thermoelectric power and spin-dependent Peltier effects. • Thermal

  8. Snakes and spin rotators

    International Nuclear Information System (INIS)

    Lee, S.Y.

    1990-01-01

    The generalized snake configuration offers advantages of either shorter total snake length and smaller orbit displacement in the compact configuration or the multi-functions in the split configuration. We found that the compact configuration can save about 10% of the total length of a snake. On other hand, the spilt snake configuration can be used both as a snake and as a spin rotator for the helicity state. Using the orbit compensation dipoles, the spilt snake configuration can be located at any distance on both sides of the interaction point of a collider provided that there is no net dipole rotation between two halves of the snake. The generalized configuration is then applied to the partial snake excitation. Simple formula have been obtained to understand the behavior of the partial snake. Similar principle can also be applied to the spin rotators. We also estimate the possible snake imperfections are due to various construction errors of the dipole magnets. Accuracy of field error of better than 10 -4 will be significant. 2 refs., 5 figs

  9. Muon spin relaxation measurements of spin-correlation decay in spin-glass AgMn

    Energy Technology Data Exchange (ETDEWEB)

    Heffner, R.H.; Cooke, D.W.; Leon, M.; Schillaci, M.E. (Los Alamos National Lab., NM (USA)); MacLaughlin, D.E.; Gupta, L.C. (California Univ., Riverside (USA))

    1984-01-01

    The field (H) dependence of the muon longitudinal spin-lattice relaxation rate well below the spin glass temperature in AgMn is found to obey an algebraic form given by (H)sup(..gamma..-1), with ..gamma.. = 0.54 +- 0.05. This suggests that Mn spin correlations decay with time as tsup(-..gamma..), in agreement with mean field theories of spin-glass dynamics which yield ..gamma..

  10. Muon spin relaxation measurements of spin-correlation decay in spin-glass AgMn

    International Nuclear Information System (INIS)

    Heffner, R.H.; Cooke, D.W.; Leon, M.; Schillaci, M.E.; MacLaughlin, D.E.; Gupta, L.C.

    1984-01-01

    The field (H) dependence of the muon longitudinal spin-lattice relaxation rate well below the spin glass temperature in AgMn is found to obey an algebraic form given by (H)sup(γ-1), with γ = 0.54 +- 0.05. This suggests that Mn spin correlations decay with time as tsup(-γ), in agreement with mean field theories of spin-glass dynamics which yield γ < approx. 0.5. Near the glass temperature the agreement between the data and theory is not as good. (Auth.)

  11. 47 CFR 80.965 - Reserve power supply.

    Science.gov (United States)

    2010-10-01

    ... conditions. When meeting this 2 hour requirement, such reserve power supply must be located on the bridge... radiotelephone must be a “reserve power supply” for the purposes of paragraphs (c), (d) and (e) of this section... meeting the requirements of paragraph (a) of this section as follows: (1) When the reserve power supply...

  12. A standard format and a graphical user interface for spin system specification.

    Science.gov (United States)

    Biternas, A G; Charnock, G T P; Kuprov, Ilya

    2014-03-01

    We introduce a simple and general XML format for spin system description that is the result of extensive consultations within Magnetic Resonance community and unifies under one roof all major existing spin interaction specification conventions. The format is human-readable, easy to edit and easy to parse using standard XML libraries. We also describe a graphical user interface that was designed to facilitate construction and visualization of complicated spin systems. The interface is capable of generating input files for several popular spin dynamics simulation packages. Copyright © 2014 The Authors. Published by Elsevier Inc. All rights reserved.

  13. Antibacterial properties of laser spinning glass nanofibers.

    Science.gov (United States)

    Echezarreta-López, M M; De Miguel, T; Quintero, F; Pou, J; Landin, M

    2014-12-30

    A laser-spinning technique has been used to produce amorphous, dense and flexible glass nanofibers of two different compositions with potential utility as reinforcement materials in composites, fillers in bone defects or scaffolds (3D structures) for tissue engineering. Morphological and microstructural analyses have been carried out using SEM-EDX, ATR-FTIR and TEM. Bioactivity studies allow the nanofibers with high proportion in SiO2 (S18/12) to be classified as a bioinert glass and the nanofibers with high proportion of calcium (ICIE16) as a bioactive glass. The cell viability tests (MTT) show high biocompatibility of the laser spinning glass nanofibers. Results from the antibacterial activity study carried out using dynamic conditions revealed that the bioactive glass nanofibers show a dose-dependent bactericidal effect on Sthaphylococcus aureus (S. aureus) while the bioinert glass nanofibers show a bacteriostatic effect also dose-dependent. The antibacterial activity has been related to the release of alkaline ions, the increase of pH of the medium and also the formation of needle-like aggregates of calcium phosphate at the surface of the bioactive glass nanofibers which act as a physical mechanism against bacteria. The antibacterial properties give an additional value to the laser-spinning glass nanofibers for different biomedical applications, such as treating or preventing surgery-associated infections. Copyright © 2014 Elsevier B.V. All rights reserved.

  14. Autonomous calibration of single spin qubit operations

    Science.gov (United States)

    Frank, Florian; Unden, Thomas; Zoller, Jonathan; Said, Ressa S.; Calarco, Tommaso; Montangero, Simone; Naydenov, Boris; Jelezko, Fedor

    2017-12-01

    Fully autonomous precise control of qubits is crucial for quantum information processing, quantum communication, and quantum sensing applications. It requires minimal human intervention on the ability to model, to predict, and to anticipate the quantum dynamics, as well as to precisely control and calibrate single qubit operations. Here, we demonstrate single qubit autonomous calibrations via closed-loop optimisations of electron spin quantum operations in diamond. The operations are examined by quantum state and process tomographic measurements at room temperature, and their performances against systematic errors are iteratively rectified by an optimal pulse engineering algorithm. We achieve an autonomous calibrated fidelity up to 1.00 on a time scale of minutes for a spin population inversion and up to 0.98 on a time scale of hours for a single qubit π/2 -rotation within the experimental error of 2%. These results manifest a full potential for versatile quantum technologies.

  15. The nuclear spin-orbit coupling

    International Nuclear Information System (INIS)

    Bell, J.S.; Skyrme, T.H.R.

    1994-01-01

    Analysis of the nucleon-nucleon scattering around 100 MeV has determined the spin-orbit coupling part of the two-body scattering matrix at that energy, and a reasonable extrapolation to lower energies is possible. This scattering amplitude has been used, in the spirit of Brueckner's nuclear model, to estimate the resultant single-body spin-orbit coupling for a single nucleon interacting with a large nucleus. This resultant potential has a radial dependence approximately proportional to r -1 d ρ /dr, and with a magnitude in good agreement with that required to explain the doublet splittings in nuclei and the polarization of nucleons scattered elastically off nuclei. (author). 14 refs, 2 figs

  16. Mean field models for spin glasses

    CERN Document Server

    Talagrand, Michel

    2011-01-01

    This is a new, completely revised, updated and enlarged edition of the author's Ergebnisse vol. 46: "Spin Glasses: A Challenge for Mathematicians". This new edition will appear in two volumes, the present first volume presents the basic results and methods, the second volume is expected to appear in 2011. In the eighties, a group of theoretical physicists introduced several models for certain disordered systems, called "spin glasses". These models are simple and rather canonical random structures, of considerable interest for several branches of science (statistical physics, neural networks and computer science). The physicists studied them by non-rigorous methods and predicted spectacular behaviors. This book introduces in a rigorous manner this exciting new area to the mathematically minded reader. It requires no knowledge whatsoever of any physics. The first volume of this new and completely rewritten edition presents six fundamental models and the basic techniques to study them.

  17. Fractional Reserve in Banking System

    OpenAIRE

    Valkonen, Maria

    2016-01-01

    This thesis is aimed to provide understanding of the role of the fractional reserve in the mod-ern banking system worldwide and particularly in Finland. The fractional reserve banking is used worldwide, but the benefits of this system are very disputable. On the one hand, experts say that the fractional reserve is a necessary instrument for the normal business and profit making. On the other hand, sceptics openly criticize the fractional reserve system and blame it for fiat money (money n...

  18. IV. Workshop on High Energy Spin Physics

    International Nuclear Information System (INIS)

    Nurushev, S.

    1992-01-01

    In this proceedings the results on high energy spin physics are summarized. The theory of spin phenomenon and the experimental results at intermediate energy and at high energy spin physics and new technical developments in polarization experiments are presented

  19. Isotropic transmission of magnon spin information without a magnetic field.

    Science.gov (United States)

    Haldar, Arabinda; Tian, Chang; Adeyeye, Adekunle Olusola

    2017-07-01

    Spin-wave devices (SWD), which use collective excitations of electronic spins as a carrier of information, are rapidly emerging as potential candidates for post-semiconductor non-charge-based technology. Isotropic in-plane propagating coherent spin waves (magnons), which require magnetization to be out of plane, is desirable in an SWD. However, because of lack of availability of low-damping perpendicular magnetic material, a usually well-known in-plane ferrimagnet yttrium iron garnet (YIG) is used with a large out-of-plane bias magnetic field, which tends to hinder the benefits of isotropic spin waves. We experimentally demonstrate an SWD that eliminates the requirement of external magnetic field to obtain perpendicular magnetization in an otherwise in-plane ferromagnet, Ni 80 Fe 20 or permalloy (Py), a typical choice for spin-wave microconduits. Perpendicular anisotropy in Py, as established by magnetic hysteresis measurements, was induced by the exchange-coupled Co/Pd multilayer. Isotropic propagation of magnon spin information has been experimentally shown in microconduits with three channels patterned at arbitrary angles.

  20. Electron refrigeration in hybrid structures with spin-split superconductors

    Science.gov (United States)

    Rouco, M.; Heikkilä, T. T.; Bergeret, F. S.

    2018-01-01

    Electron tunneling between superconductors and normal metals has been used for an efficient refrigeration of electrons in the latter. Such cooling is a nonlinear effect and usually requires a large voltage. Here we study the electron cooling in heterostructures based on superconductors with a spin-splitting field coupled to normal metals via spin-filtering barriers. The cooling power shows a linear term in the applied voltage. This improves the coefficient of performance of electron refrigeration in the normal metal by shifting its optimum cooling to lower voltage, and also allows for cooling the spin-split superconductor by reverting the sign of the voltage. We also show how tunnel coupling spin-split superconductors with regular ones allows for a highly efficient refrigeration of the latter.

  1. Superconductive analogue of spin glasses

    International Nuclear Information System (INIS)

    Feigel'man, M.; Ioffe, L.; Vinokur, V.; Larkin, A.

    1987-07-01

    The properties of granular superconductors in magnetic fields, namely the existence of a new superconductive state analogue of the low-temperature superconductive state in spin glasses are discussed in the frame of the infinite-range model and the finite-range models. Experiments for elucidation of spin-glass superconductive state in real systems are suggested. 30 refs

  2. Nuclear Spins in Quantum Dots

    NARCIS (Netherlands)

    Erlingsson, S.I.

    2003-01-01

    The main theme of this thesis is the hyperfine interaction between the many lattice nuclear spins and electron spins localized in GaAs quantum dots. This interaction is an intrinsic property of the material. Despite the fact that this interaction is rather weak, it can, as shown in this thesis,

  3. SPIN PHYSICS: Lasers at work

    International Nuclear Information System (INIS)

    Anon.

    1992-01-01

    Lasers are now an everyday tool in particle physics, particularly for the spin polarization of beams, targets, and even short-lived particles. Development has been boosted in recent years by the availability of reliable multiwatt tunable lasers to select spin in an experimentally useful sample

  4. Universal intrinsic spin Hall effect

    Czech Academy of Sciences Publication Activity Database

    Sinova, J.; Culcer, D.; Sinitsyn, N. A.; Niu, Q.; Jungwirth, Tomáš; MacDonald, A. H.

    2004-01-01

    Roč. 92, č. 12 (2004), 126603/1-126603/4 ISSN 0031-9007 R&D Projects: GA ČR GA202/02/0912 Institutional research plan: CEZ:AV0Z1010914 Keywords : semiconductor quantum wells * spin-orbit interaction * spin Hall effect Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 7.218, year: 2004

  5. Spin Hall effect for anyons

    International Nuclear Information System (INIS)

    Dhar, S.; Basu, B.; Ghosh, Subir

    2007-01-01

    We explain the intrinsic spin Hall effect from generic anyon dynamics in the presence of external electromagnetic field. The free anyon is represented as a spinning particle with an underlying non-commutative configuration space. The Berry curvature plays a major role in the analysis

  6. Spin-photon entangling diode

    DEFF Research Database (Denmark)

    Flindt, Christian; Sørensen, A. S.; Lukin, M. D.

    2007-01-01

    We propose a semiconductor device that can electrically generate entangled electron spin-photon states, providing a building block for entanglement of distant spins. The device consists of a p-i-n diode structure that incorporates a coupled double quantum dot. We show that electronic control of t...

  7. Integrable multiparametric quantum spin chains

    CERN Document Server

    Förster, A; Roditi, I; Foerster, Angela; Links, Jon; Roditi, Itzhak

    1998-01-01

    Using Reshetikhin's construction for multiparametric quantum algebras we obtain the associated multiparametric quantum spin chains. We show that under certain restrictions these models can be mapped to quantum spin chains with twisted boundary conditions. We illustrate how this general formalism applies to construct multiparametric versions of the supersymmetric t-J and U models.

  8. 7 CFR 1467.9 - Wetlands Reserve Enhancement Program.

    Science.gov (United States)

    2010-01-01

    ..., restoration, and enhancement objectives through agreements with States (including a political subdivision or... project. (b) Reserved Rights Pilot. (1) The Chief shall carry out a reserved rights pilot subject to the requirements established in this part. (2) Under the reserved rights pilot, a landowner may reserve grazing...

  9. Double-quantum homonuclear correlations of spin I=5/2 nuclei.

    Science.gov (United States)

    Iuga, Dinu

    2011-02-01

    The challenges associated with acquiring double-quantum homonuclear Nuclear Magnetic Resonance correlation spectra of half-integer quadrupolar nuclei are described. In these experiments the radio-frequency irradiation amplitude is necessarily weak in order to selectively excite the central transition. In this limit only one out of the 25 double-quantum coherences possible for two coupled spin I=5/2 nuclei is excited. An investigation of all the 25 two spins double quantum transitions reveals interesting effects such as a compensation of the first-order quadrupolar interaction between the two single quantum transitions involved in the double quantum coherence. In this paper a full numerical study of a hypothetical two spin I=5/2 system is used to show what happens when the RF amplitude during recoupling is increased. In principle this is advantageous, since the required double quantum coherence should build up faster, but in practice it also induces adiabatic passage transfer of population and coherence which impedes any build up. Finally an optimized rotary resonance recoupling (oR(3)) sequence is introduced in order to decrease these transfers. This sequence consists of a spin locking irradiation whose amplitude is reduced four times during one rotor period, and allows higher RF powers to be used during recoupling. The sequence is used to measure (27)Al DQ dipolar correlation spectra of Y(3)Al(5)O(12) (YAG) and gamma alumina (γAl(2)O(3)). The results prove that aluminium vacancies in gamma alumina mainly occur in the tetrahedral sites. Copyright © 2010 Elsevier Inc. All rights reserved.

  10. Spin noise spectroscopy of ZnO

    Science.gov (United States)

    Horn, H.; Berski, F.; Balocchi, A.; Marie, X.; Mansur-Al-Suleiman, M.; Bakin, A.; Waag, A.; Hübner, J.; Oestreich, M.

    2013-12-01

    We investigate the thermal equilibrium dynamics of electron spins bound to donors in nanoporous ZnO by optical spin noise spectroscopy. The spin noise spectra reveal two noise contributions: A weak spin noise signal from undisturbed localized donor electrons with a dephasing time of 24 ns due to hyperfine interaction and a strong spin noise signal with a spin dephasing time of 5 ns which we attribute to localized donor electrons which interact with lattice defects.

  11. Spin noise spectroscopy of ZnO

    Energy Technology Data Exchange (ETDEWEB)

    Horn, H.; Berski, F.; Hübner, J.; Oestreich, M. [Institute for Solid State Physics, Leibniz Universität Hannover, Appelstr. 2, 30167 Hannover (Germany); Balocchi, A.; Marie, X. [INSA-CNRS-UPS, LPCNO, Université de Toulouse, 135 Av. de Rangueil, 31077 Toulouse (France); Mansur-Al-Suleiman, M.; Bakin, A.; Waag, A. [Institute of Semiconductor Technology, Technische Universität Braunschweig, Hans-Sommer-Straße 66, 38106 Braunschweig (Germany)

    2013-12-04

    We investigate the thermal equilibrium dynamics of electron spins bound to donors in nanoporous ZnO by optical spin noise spectroscopy. The spin noise spectra reveal two noise contributions: A weak spin noise signal from undisturbed localized donor electrons with a dephasing time of 24 ns due to hyperfine interaction and a strong spin noise signal with a spin dephasing time of 5 ns which we attribute to localized donor electrons which interact with lattice defects.

  12. On the concept of spin

    International Nuclear Information System (INIS)

    Pestov, I.B.

    1997-01-01

    It is substantiated that spin is a notion associated with the group of internal symmetry that is tightly connected with the geometrical structure of spacetime. The wave equation for the description of a particle with spin one half is proposed. On this ground it is shown that the spin of electron is exhibited through the quantum number and accordingly the Dirac equation describes properties of particles with the projection of spin ±h/2. On the contrary, we put forward the conjecture that the spin of the quark cannot be considered as a quantum number, but only as an origin of a non-abelian gauge field. The reason is that the quark and electron from physical, geometrical and group-theoretical points of view differ from each other. It is a deep reason for understanding quark-lepton symmetry and such important phenomena as quark confinement

  13. Disorder and Quantum Spin Ice

    Science.gov (United States)

    Martin, N.; Bonville, P.; Lhotel, E.; Guitteny, S.; Wildes, A.; Decorse, C.; Ciomaga Hatnean, M.; Balakrishnan, G.; Mirebeau, I.; Petit, S.

    2017-10-01

    We report on diffuse neutron scattering experiments providing evidence for the presence of random strains in the quantum spin-ice candidate Pr2Zr2O7 . Since Pr3 + is a non-Kramers ion, the strain deeply modifies the picture of Ising magnetic moments governing the low-temperature properties of this material. It is shown that the derived strain distribution accounts for the temperature dependence of the specific heat and of the spin-excitation spectra. Taking advantage of mean-field and spin-dynamics simulations, we argue that the randomness in Pr2Zr2O7 promotes a new state of matter, which is disordered yet characterized by short-range antiferroquadrupolar correlations, and from which emerge spin-ice-like excitations. Thus, this study gives an original research route in the field of quantum spin ice.

  14. Spin-3 topologically massive gravity

    Energy Technology Data Exchange (ETDEWEB)

    Chen Bin, E-mail: bchen01@pku.edu.cn [Department of Physics, and State Key Laboratory of Nuclear Physics and Technology, Peking University, Beijing 100871 (China); Center for High Energy Physics, Peking University, Beijing 100871 (China); Long Jiang, E-mail: longjiang0301@gmail.com [Department of Physics, and State Key Laboratory of Nuclear Physics and Technology, Peking University, Beijing 100871 (China); Wu Junbao, E-mail: wujb@ihep.ac.cn [Institute of High Energy Physics, and Theoretical Physics Center for Science Facilities, Chinese Academy of Sciences, Beijing 100049 (China)

    2011-11-24

    In this Letter, we study the spin-3 topologically massive gravity (TMG), paying special attention to its properties at the chiral point. We propose an action describing the higher spin fields coupled to TMG. We discuss the traceless spin-3 fluctuations around the AdS{sub 3} vacuum and find that there is an extra local massive mode, besides the left-moving and right-moving boundary massless modes. At the chiral point, such extra mode becomes massless and degenerates with the left-moving mode. We show that at the chiral point the only degrees of freedom in the theory are the boundary right-moving graviton and spin-3 field. We conjecture that spin-3 chiral gravity with generalized Brown-Henneaux boundary condition is holographically dual to 2D chiral CFT with classical W{sub 3} algebra and central charge c{sub R}=3l/G.

  15. A spin exchange model for singlet fission

    Science.gov (United States)

    Yago, Tomoaki; Wakasa, Masanobu

    2018-03-01

    Singlet fission has been analyzed with the Dexter model in which electron exchange occurs between chromophores, conserving the spin for each electron. In the present study, we propose a spin exchange model for singlet fission. In the spin exchange model, spins are exchanged by the exchange interaction between two electrons. Our analysis with simple spin functions demonstrates that singlet fission is possible by spin exchange. A necessary condition for spin exchange is a variation in exchange interactions. We also adapt the spin exchange model to triplet fusion and triplet energy transfer, which often occur after singlet fission in organic solids.

  16. Spin-lattice relaxation of individual solid-state spins

    Science.gov (United States)

    Norambuena, A.; Muñoz, E.; Dinani, H. T.; Jarmola, A.; Maletinsky, P.; Budker, D.; Maze, J. R.

    2018-03-01

    Understanding the effect of vibrations on the relaxation process of individual spins is crucial for implementing nanosystems for quantum information and quantum metrology applications. In this work, we present a theoretical microscopic model to describe the spin-lattice relaxation of individual electronic spins associated to negatively charged nitrogen-vacancy centers in diamond, although our results can be extended to other spin-boson systems. Starting from a general spin-lattice interaction Hamiltonian, we provide a detailed description and solution of the quantum master equation of an electronic spin-one system coupled to a phononic bath in thermal equilibrium. Special attention is given to the dynamics of one-phonon processes below 1 K where our results agree with recent experimental findings and analytically describe the temperature and magnetic-field scaling. At higher temperatures, linear and second-order terms in the interaction Hamiltonian are considered and the temperature scaling is discussed for acoustic and quasilocalized phonons when appropriate. Our results, in addition to confirming a T5 temperature dependence of the longitudinal relaxation rate at higher temperatures, in agreement with experimental observations, provide a theoretical background for modeling the spin-lattice relaxation at a wide range of temperatures where different temperature scalings might be expected.

  17. Spin manipulation and relaxation in spin-orbit qubits

    Science.gov (United States)

    Borhani, Massoud; Hu, Xuedong

    2012-03-01

    We derive a generalized form of the electric dipole spin resonance (EDSR) Hamiltonian in the presence of the spin-orbit interaction for single spins in an elliptic quantum dot (QD) subject to an arbitrary (in both direction and magnitude) applied magnetic field. We predict a nonlinear behavior of the Rabi frequency as a function of the magnetic field for sufficiently large Zeeman energies, and present a microscopic expression for the anisotropic electron g tensor. Similarly, an EDSR Hamiltonian is devised for two spins confined in a double quantum dot (DQD), where coherent Rabi oscillations between the singlet and triplet states are induced by jittering the inter-dot distance at the resonance frequency. Finally, we calculate two-electron-spin relaxation rates due to phonon emission, for both in-plane and perpendicular magnetic fields. Our results have immediate applications to current EDSR experiments on nanowire QDs, g-factor optimization of confined carriers, and spin decay measurements in DQD spin-orbit qubits.

  18. Studies on spin waves

    International Nuclear Information System (INIS)

    Prets, A.

    1998-07-01

    In the present Ph. D. thesis we are considering a special form of scaling limits, namely the hydrodynamic limit. Such limits are considered to explain macroscopic behavior of matter by means of microscopic dynamic laws. In this procedure a rescaling of space and time plays a central role. The limit will be formulated in a quantum mechanical way. Within this framework we study derivations of the Landau Lifshitz equation for ferromagnets. This equation is a macroscopic equation of motion for the magnetization vector and results into the theory of spin waves. Since we have no exact knowledge of the Heisenberg operator's time evolution no definitive statement an how to regain the Landau Lifshitz equation from the microscopic dynamics can be given. In contrast to the Heisenberg operator, for an Ising type interaction inside a ferromagnet one is able to recover macroscopically a solution of a linearized Landau Lifschitz equation. (author)

  19. Spin fluctuations and the

    Directory of Open Access Journals (Sweden)

    V.M. Loktev

    2008-09-01

    Full Text Available We analyze the spectral properties of a phenomenological model for a weakly doped two-dimensional antiferromagnet, in which the carriers move within one of the two sublattices where they were introduced. Such a constraint results in the free carrier spectra with the maxima at k=(± π/2 , ± π/2 observed in some cuprates. We consider the spectral properties of the model by taking into account fluctuations of the spins in the antiferromagnetic background. We show that such fluctuations lead to a non-pole-like structure of the single-hole Green's function and these fluctuations can be responsible for some anomalous "strange metal" properties of underdoped cuprates in the nonsuperconducting regime.

  20. Spin Orbit Interaction Engineering for beyond Spin Transfer Torque memory

    Science.gov (United States)

    Wang, Kang L.

    Spin transfer torque memory uses electron current to transfer the spin torque of electrons to switch a magnetic free layer. This talk will address an alternative approach to energy efficient non-volatile spintronics through engineering of spin orbit interaction (SOC) and the use of spin orbit torque (SOT) by the use of electric field to improve further the energy efficiency of switching. I will first discuss the engineering of interface SOC, which results in the electric field control of magnetic moment or magneto-electric (ME) effect. Magnetic memory bits based on this ME effect, referred to as magnetoelectric RAM (MeRAM), is shown to have orders of magnitude lower energy dissipation compared with spin transfer torque memory (STTRAM). Likewise, interests in spin Hall as a result of SOC have led to many advances. Recent demonstrations of magnetization switching induced by in-plane current in heavy metal/ferromagnetic heterostructures have been shown to arise from the large SOC. The large SOC is also shown to give rise to the large SOT. Due to the presence of an intrinsic extraordinarily strong SOC and spin-momentum lock, topological insulators (TIs) are expected to be promising candidates for exploring spin-orbit torque (SOT)-related physics. In particular, we will show the magnetization switching in a chromium-doped magnetic TI bilayer heterostructure by charge current. A giant SOT of more than three orders of magnitude larger than those reported in heavy metals is also obtained. This large SOT is shown to come from the spin-momentum locked surface states of TI, which may further lead to innovative low power applications. I will also describe other related physics of SOC at the interface of anti-ferromagnetism/ferromagnetic structure and show the control exchange bias by electric field for high speed memory switching. The work was in part supported by ERFC-SHINES, NSF, ARO, TANMS, and FAME.

  1. Competing Spin Liquids and Hidden Spin-Nematic Order in Spin Ice with Frustrated Transverse Exchange

    Directory of Open Access Journals (Sweden)

    Mathieu Taillefumier

    2017-12-01

    Full Text Available Frustration in magnetic interactions can give rise to disordered ground states with subtle and beautiful properties. The spin ices Ho_{2}Ti_{2}O_{7} and Dy_{2}Ti_{2}O_{7} exemplify this phenomenon, displaying a classical spin-liquid state, with fractionalized magnetic-monopole excitations. Recently, there has been great interest in closely related “quantum spin-ice” materials, following the realization that anisotropic exchange interactions could convert spin ice into a massively entangled, quantum spin liquid, where magnetic monopoles become the charges of an emergent quantum electrodynamics. Here we show that even the simplest model of a quantum spin ice, the XXZ model on the pyrochlore lattice, can realize a still-richer scenario. Using a combination of classical Monte Carlo simulation, semiclassical molecular-dynamics simulation, and analytic field theory, we explore the properties of this model for frustrated transverse exchange. We find not one, but three competing forms of spin liquid, as well as a phase with hidden, spin-nematic order. We explore the experimental signatures of each of these different states, making explicit predictions for inelastic neutron scattering. These results show an intriguing similarity to experiments on a range of pyrochlore oxides.

  2. 7 CFR 3560.306 - Reserve account.

    Science.gov (United States)

    2010-01-01

    ... be deemed to contain surplus funds when the balance at the end of the housing project's fiscal year...) As projects age, the required reserve account level may be adjusted to meet anticipated “life-cycle..., identity-of-interest, cost-reasonableness, and construction management apply to any work or services paid...

  3. Biosphere reserves: Attributes for success.

    Science.gov (United States)

    Van Cuong, Chu; Dart, Peter; Hockings, Marc

    2017-03-01

    Biosphere reserves established under the UNESCO Man and the Biosphere Program aim to harmonise biodiversity conservation and sustainable development. Concerns over the extent to which the reserve network was living up to this ideal led to the development of a new strategy in 1995 (the Seville Strategy) to enhance the operation of the network of reserves. An evaluation of effectiveness of management of the biosphere reserve network was called for as part of this strategy. Expert opinion was assembled through a Delphi Process to identify successful and less successful reserves and investigate common factors influencing success or failure. Ninety biosphere reserves including sixty successful and thirty less successful reserves in 42 countries across all five Man and the Biosphere Program regions were identified. Most successful sites are the post-Seville generation while the majority of unsuccessful sites are pre-Seville that are managed as national parks and have not been amended to conform to the characteristics that are meant to define a biosphere reserve. Stakeholder participation and collaboration, governance, finance and resources, management, and awareness and communication are the most influential factors in the success or failure of the biosphere reserves. For success, the biosphere reserve concept needs to be clearly understood and applied through landscape zoning. Designated reserves then need a management system with inclusive good governance, strong participation and collaboration, adequate finance and human resource allocation and stable and responsible management and implementation. All rather obvious but it is difficult to achieve without commitment to the biosphere reserve concept by the governance authorities. Copyright © 2016 Elsevier Ltd. All rights reserved.

  4. Separating inverse spin Hall voltage and spin rectification voltage by inverting spin injection direction

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Wenxu, E-mail: xwzhang@uestc.edu.cn; Peng, Bin; Han, Fangbin; Wang, Qiuru; Zhang, Wanli [State Key Laboratory of Electronic Thin Films and Integrated Devices, University of Electronic Science and Technology of China, Chengdu 610054 (China); Soh, Wee Tee; Ong, Chong Kim [Center for Superconducting and Magnetic Materials, Department of Physics, National University of Singapore, 2 Science Drive 3, Singapore 117551 (Singapore)

    2016-03-07

    We develop a method for universally resolving the important issue of separating the inverse spin Hall effect (ISHE) from the spin rectification effect (SRE) signal. This method is based on the consideration that the two effects depend on the spin injection direction: The ISHE is an odd function of the spin injection direction while the SRE is independent on it. Thus, the inversion of the spin injection direction changes the ISHE voltage signal, while the SRE voltage remains. It applies generally to analyzing the different voltage contributions without fitting them to special line shapes. This fast and simple method can be used in a wide frequency range and has the flexibility of sample preparation.

  5. How to control spin-Seebeck current in a metal-quantum dot-magnetic insulator junction

    Science.gov (United States)

    Fu, Hua-Hua; Gu, Lei; Wu, Ruqian

    The control of the spin-Seebeck current is still a challenging task for the development of spin caloritronic devices. Here, we construct a spin-Seebeck device by inserting a quantum dot (QD) between the metal lead and magnetic insulator. Using the slave-particle approach and noncrossing approximation, we find that the spin-Seebeck effect increases significantly when the energy level of the QD locates near the Fermi level of the metal lead due to the enhancement of spin flipping and occurrences of quantum resonance. Since this can be easily realized by applying a gate voltage in experiments, the spin-Seebeck device proposed here can also work as a thermovoltaic transistor. Moreover, the optimal correlation strength and the energy level position of the QD are discussed to maximize the spin-Seebeck current as required for applications in controllable spin caloritronic devices.

  6. How to realize a spin-dependent Seebeck diode effect in metallic zigzag γ-graphyne nanoribbons?

    Science.gov (United States)

    Wu, Dan-Dan; Liu, Qing-Bo; Fu, Hua-Hua; Wu, Ruqian

    2017-11-30

    The spin-dependent Seebeck effect (SDSE) is one of the core topics of spin caloritronics. In the traditional device designs of spin-dependent Seebeck rectifiers and diodes, finite spin-dependent band gaps of materials are required to realize the on-off characteristic in thermal spin currents, and nearly zero charge current should be achieved to reduce energy dissipation. Here, we propose that two ferromagnetic zigzag γ-graphyne nanoribbons (ZγGNRs) without any spin-dependent band gaps around the Fermi level can not only exhibit the SDSE, but also display rectifier and diode effects in thermal spin currents characterized by threshold temperatures, which originates from the compensation effect occurring in spin-dependent transmissions but not from the spin-splitting band gaps in materials. The metallic characteristics of ZγGNRs bring about an advantage that the gate voltage is an effective route to adjust the symmetry of spin-splitting bands to obtain pure thermal spin currents. The results provide a new mechanism to realize spin-Seebeck rectifier and diode effects in 2D materials and expand material candidates towards spin-Seebeck device applications.

  7. Spin transport in epitaxial graphene

    Science.gov (United States)

    Tbd, -

    2014-03-01

    Spintronics is a paradigm focusing on spin as the information vector in fast and ultra-low-power non volatile devices such as the new STT-MRAM. Beyond its widely distributed application in data storage it aims at providing more complex architectures and a powerful beyond CMOS solution for information processing. The recent discovery of graphene has opened novel exciting opportunities in terms of functionalities and performances for spintronics devices. We will present experimental results allowing us to assess the potential of graphene for spintronics. We will show that unprecedented highly efficient spin information transport can occur in epitaxial graphene leading to large spin signals and macroscopic spin diffusion lengths (~ 100 microns), a key enabler for the advent of envisioned beyond-CMOS spin-based logic architectures. We will also show that how the device behavior is well explained within the framework of the Valet-Fert drift-diffusion equations. Furthermore, we will show that a thin graphene passivation layer can prevent the oxidation of a ferromagnet, enabling its use in novel humide/ambient low-cost processes for spintronics devices, while keeping its highly surface sensitive spin current polarizer/analyzer behavior and adding new enhanced spin filtering property. These different experiments unveil promising uses of graphene for spintronics.

  8. Reserves Represented by Random Walks

    International Nuclear Information System (INIS)

    Filipe, J A; Ferreira, M A M; Andrade, M

    2012-01-01

    The reserves problem is studied through models based on Random Walks. Random walks are a classical particular case in the analysis of stochastic processes. They do not appear only to study reserves evolution models. They are also used to build more complex systems and as analysis instruments, in a theoretical feature, of other kind of systems. In this work by studying the reserves, the main objective is to see and guarantee that pensions funds get sustainable. Being the use of these models considering this goal a classical approach in the study of pensions funds, this work concluded about the problematic of reserves. A concrete example is presented.

  9. The Economics of NASA Mission Cost Reserves

    Science.gov (United States)

    Whitley, Sally; Shinn, Stephen

    2012-01-01

    Increases in NASA mission costs are well-noted but not well-understood, and there is little evidence that they are decreasing in frequency or amount over time. The need to control spending has led to analysis of the causes and magnitude of historical mission overruns, and many program control efforts are being implemented to attempt to prevent or mitigate the problem (NPR 7120). However, cost overruns have not abated, and while some direct causes of increased spending may be obvious (requirements creep, launch delays, directed changes, etc.), the underlying impetus to spend past the original budget may be more subtle. Gaining better insight into the causes of cost overruns will help NASA and its contracting organizations to avoid .them. This paper hypothesizes that one cause of NASA mission cost overruns is that the availability of reserves gives project team members an incentive to make decisions and behave in ways that increase costs. We theorize that the presence of reserves is a contributing factor to cost overruns because it causes organizations to use their funds less efficiently or to control spending less effectively. We draw a comparison to the insurance industry concept of moral hazard, the phenomenon that the presence of insurance causes insureds to have more frequent and higher insurance losses, and we attempt to apply actuarial techniques to quantifY the increase in the expected cost of a mission due to the availability of reserves. We create a theoretical model of reserve spending motivation by defining a variable ReserveSpending as a function of total reserves. This function has a positive slope; for every dollar of reserves available, there is a positive probability of spending it. Finally, the function should be concave down; the probability of spending each incremental dollar of reserves decreases progressively. We test the model against available NASA CADRe data by examining missions with reserve dollars initially available and testing whether

  10. Spin Filters as High-Performance Spin Polarimeters

    International Nuclear Information System (INIS)

    Rougemaille, N.; Lampel, G.; Peretti, J.; Drouhin, H.-J.; Lassailly, Y.; Filipe, A.; Wirth, T.; Schuhl, A.

    2003-01-01

    A spin-dependent transport experiment in which hot electrons pass through a ferromagnetic metal / semiconductor Schottky diode has been performed. A spin-polarized free-electron beam, emitted in vacuum from a GaAs photocathode, is injected into the thin metal layer with an energy between 5 and 1000 eV above to the Fermi level. The transmitted current collected in the semiconductor substrate increases with injection energy because of secondary - electron multiplication. The spin-dependent part of the transmitted current is first constant up to about 100 eV and then increases by 4 orders of magnitude. As an immediate application, the solid-state hybrid structure studied here leads to a very efficient and compact device for spin polarization detection

  11. Spin Hall effect-driven spin torque in magnetic textures

    KAUST Repository

    Manchon, Aurelien; Lee, K.-J.

    2011-01-01

    Current-induced spin torque and magnetization dynamics in the presence of spin Hall effect in magnetic textures is studied theoretically. The local deviation of the charge current gives rise to a current-induced spin torque of the form (1 - ΒM) × [(u 0 + αH u 0 M) ∇] M, where u0 is the direction of the injected current, H is the Hall angle and is the non-adiabaticity parameter due to spin relaxation. Since αH and ×can have a comparable order of magnitude, we show that this torque can significantly modify the current-induced dynamics of both transverse and vortex walls. © 2011 American Institute of Physics.

  12. Spin Hall effect-driven spin torque in magnetic textures

    KAUST Repository

    Manchon, Aurelien

    2011-07-13

    Current-induced spin torque and magnetization dynamics in the presence of spin Hall effect in magnetic textures is studied theoretically. The local deviation of the charge current gives rise to a current-induced spin torque of the form (1 - ΒM) × [(u 0 + αH u 0 M) ∇] M, where u0 is the direction of the injected current, H is the Hall angle and is the non-adiabaticity parameter due to spin relaxation. Since αH and ×can have a comparable order of magnitude, we show that this torque can significantly modify the current-induced dynamics of both transverse and vortex walls. © 2011 American Institute of Physics.

  13. Spin Hall effect and Berry phase of spinning particles

    International Nuclear Information System (INIS)

    Berard, Alain; Mohrbach, Herve

    2006-01-01

    We consider the adiabatic evolution of the Dirac equation in order to compute its Berry curvature in momentum space. It is found that the position operator acquires an anomalous contribution due to the non-Abelian Berry gauge connection making the quantum mechanical algebra noncommutative. A generalization to any known spinning particles is possible by using the Bargmann-Wigner equation of motions. The noncommutativity of the coordinates is responsible for the topological spin transport of spinning particles similarly to the spin Hall effect in spintronic physics or the Magnus effect in optics. As an application we predict new dynamics for nonrelativistic particles in an electric field and for photons in a gravitational field

  14. Spin Currents and Spin Orbit Torques in Ferromagnets and Antiferromagnets

    Science.gov (United States)

    Hung, Yu-Ming

    This thesis focuses on the interactions of spin currents and materials with magnetic order, e.g., ferromagnetic and antiferromagnetic thin films. The spin current is generated in two ways. First by spin-polarized conduction-electrons associated with the spin Hall effect in heavy metals (HMs) and, second, by exciting spin-waves in ferrimagnetic insulators using a microwave frequency magnetic field. A conduction-electron spin current can be generated by spin-orbit coupling in a heavy non-magnetic metal and transfer its spin angular momentum to a ferromagnet, providing a means of reversing the magnetization of perpendicularly magnetized ultrathin films with currents that flow in the plane of the layers. The torques on the magnetization are known as spin-orbit torques (SOT). In the first part of my thesis project I investigated and contrasted the quasistatic (slowly swept current) and pulsed current-induced switching characteristics of micrometer scale Hall crosses consisting of very thin (magnetized CoFeB layers on beta-Ta. While complete magnetization reversal occurs at a threshold current density in the quasistatic case, pulses with short duration (≤10 ns) and larger amplitude (≃10 times the quasistatic threshold current) lead to only partial magnetization reversal and domain formation. The partial reversal is associated with the limited time for reversed domain expansion during the pulse. The second part of my thesis project studies and considers applications of SOT-driven domain wall (DW) motion in a perpendicularly magnetized ultrathin ferromagnet sandwiched between a heavy metal and an oxide. My experiment results demonstrate that the DW motion can be explained by a combination of the spin Hall effect, which generates a SOT, and Dzyaloshinskii-Moriya interaction, which stabilizes chiral Neel-type DW. Based on SOT-driven DW motion and magnetic coupling between electrically isolated ferromagnetic elements, I proposed a new type of spin logic devices. I then

  15. Neutralino spin measurement with ATLAS

    CERN Document Server

    Ventura, A

    2007-01-01

    One of the goals of the ATLAS experiment at the LHC is to search for evidence of Supersymmetry (SUSY) signals and to measure, if discovered, the main properties of the new particles, like the spin. Left-handed squark cascade decay to second lightest neutralino which further decays to slepton represents a good opportunity for SUSY particles' spin measurement. The observability of charge asymmetries in invariant mass distributions of some final products is investigated to prove that neutralino spin is 1/2. The criteria used to select signal events and to reject background are described, together with the applied cut efficiencies. Results on charge asymmetry are then shown and discussed.

  16. FERMILAB: High energy spin effects

    Energy Technology Data Exchange (ETDEWEB)

    Anon.

    1991-03-15

    While many physicists would agree that it is important to study interactions of different isospin states (for example comparing proton and neutron data), many of them also accept as normal data averaged or integrated over ordinary spin. However an ongoing programme at Brookhaven studying elastic scattering (where the incoming particles 'bounce' off each other) produced marked spin effects which are not well understood. Our understanding of particle interactions should not be influenced by which observables are easy to measure and which aren't, and until a clear understanding of spin effects emerges, it is important to continue and extend these studies.

  17. Spin orientation for nearby galaxies

    International Nuclear Information System (INIS)

    Karachentsev, I.D.

    1989-01-01

    The spatial orientations and the absolute values of angular momentum are determined for galaxies in the Local Group and the M 81/IC 342 group. For this purpose, the data on both velocity field and the dust knots configuration have been used. The spin direction has been established unambiguously for 21 objects; however, for the remaining 14 dwarf members the spin orientations are presented by pairs of alternative directions. The distribution of the spin vectors on the sky does not slow pronounced sings of anisotropy

  18. Summary of spin physics sessions

    International Nuclear Information System (INIS)

    Roser, T.

    1988-01-01

    The list of topics in the many talks given during the Spin Physics sessions of this Intersections conference is nearly as long as the one of this conference: P and T Violation NN Interaction πp and πd Elastic Scattering Nuclear Matter Spin Effects Muon (g-2) Polarized Proton Beams Polarized Gas Targets This points to the almost trivial fact that spin is fundamental to our understanding of nuclear and particle physics. I will discuss in some detail only four of these topics. Needless to say this choice is very much personally biased and I apologize to all the speakers whose excellent contributions I did not include

  19. Spin structures in antiferromagnetic nanoparticles

    DEFF Research Database (Denmark)

    Brok, Erik

    dependence of the magnetisation in certain nanoparticle systems, as welll bulk systems with spin canting due to defects. In accordance with this model magnetisation measurements on goethtie (a-FeOOH) nanoparticles are presented, showing a low temperature increase in the magnetisation. The spin orientation...... experimental data from unpolarised neutron diffraction. The spin orientation is found to be close to the particle plane, which is the (111) plane of the FCC structure of NiO for particles with thickness ranging from 2.2 nm to bulk (= 200 nm) particles. In the smallest particles, with a thickness of 2.0 nm, we...

  20. Spinning fluids in general relativity

    Science.gov (United States)

    Ray, J. R.; Smalley, L. L.

    1982-01-01

    General relativity field equations are employed to examine a continuous medium with internal spin. A variational principle formerly applied in the special relativity case is extended to the general relativity case, using a tetrad to express the spin density and the four-velocity of the fluid. An energy-momentum tensor is subsequently defined for a spinning fluid. The equations of motion of the fluid are suggested to be useful in analytical studies of galaxies, for anisotropic Bianchi universes, and for turbulent eddies.

  1. Spin-spin correlations in the tt'-Hubbard model

    International Nuclear Information System (INIS)

    Husslein, T.; Newns, D.M.; Mattutis, H.G.; Pattnaik, P.C.; Morgenstern, I.; Singer, J.M.; Fettes, W.; Baur, C.

    1994-01-01

    We present calculations of the tt'-Hubbard model using Quantum Monte Carlo techniques. The parameters are chosen so that the van Hove Singularity in the density of states and the Fermi level coincide. We study the behaviour of the system with increasing Hubbard interaction U. Special emphasis is on the spin-spin correlation (SSC). Unusual behaviour for large U is observed there and in the momentum distribution function (n(q)). (orig.)

  2. High-field spin dynamics of antiferromagnetic quantum spin chains

    DEFF Research Database (Denmark)

    Enderle, M.; Regnault, L.P.; Broholm, C.

    2000-01-01

    present recent work on the high-field spin dynamics of the S = I antiferromagnetic Heisenberg chains NENP (Haldane ground state) and CsNiCl3 (quasi-1D HAF close to the quantum critical point), the uniform S = 1/2 chain CTS, and the spin-Peierls system CuGeO3. (C) 2000 Elsevier Science B,V. All rights...

  3. Beam Splitter for Spin Waves in Quantum Spin Network

    OpenAIRE

    Yang, S.; Song, Z.; Sun, C. P.

    2005-01-01

    We theoretically design and analytically study a controllable beam splitter for the spin wave propagating in a star-shaped (e.g., a $Y$-shaped beam) spin network. Such a solid state beam splitter can display quantum interference and quantum entanglement by the well-aimed controls of interaction on nodes. It will enable an elementary interferometric device for scalable quantum information processing based on the solid system.

  4. Single spin asymmetries and the spin of the proton

    International Nuclear Information System (INIS)

    Dominguez Z, G.; Herrera C, G.

    2000-01-01

    We study the spin asymmetries of inclusive π + , π 0 , π - , η and γ production in the interaction of a polarized with a non polarized proton, in the frame of a two component model. Particle production in the model is assumed to consist of a conventional QCD fragmentation process plus a recombination mechanism. The presence of Thomas precession in the recombination process seems to be responsible for the production spin asymmetry. (Author) 12 refs., 8 figs

  5. Tuning the effective spin-orbit coupling in molecular semiconductors

    KAUST Repository

    Schott, Sam

    2017-05-11

    The control of spins and spin to charge conversion in organics requires understanding the molecular spin-orbit coupling (SOC), and a means to tune its strength. However, quantifying SOC strengths indirectly through spin relaxation effects has proven difficult due to competing relaxation mechanisms. Here we present a systematic study of the g-tensor shift in molecular semiconductors and link it directly to the SOC strength in a series of high-mobility molecular semiconductors with strong potential for future devices. The results demonstrate a rich variability of the molecular g-shifts with the effective SOC, depending on subtle aspects of molecular composition and structure. We correlate the above g-shifts to spin-lattice relaxation times over four orders of magnitude, from 200 to 0.15 μs, for isolated molecules in solution and relate our findings for isolated molecules in solution to the spin relaxation mechanisms that are likely to be relevant in solid state systems.

  6. Tuning the effective spin-orbit coupling in molecular semiconductors

    KAUST Repository

    Schott, Sam; McNellis, Erik R.; Nielsen, Christian B.; Chen, Hung-Yang; Watanabe, Shun; Tanaka, Hisaaki; McCulloch, Iain; Takimiya, Kazuo; Sinova, Jairo; Sirringhaus, Henning

    2017-01-01

    The control of spins and spin to charge conversion in organics requires understanding the molecular spin-orbit coupling (SOC), and a means to tune its strength. However, quantifying SOC strengths indirectly through spin relaxation effects has proven difficult due to competing relaxation mechanisms. Here we present a systematic study of the g-tensor shift in molecular semiconductors and link it directly to the SOC strength in a series of high-mobility molecular semiconductors with strong potential for future devices. The results demonstrate a rich variability of the molecular g-shifts with the effective SOC, depending on subtle aspects of molecular composition and structure. We correlate the above g-shifts to spin-lattice relaxation times over four orders of magnitude, from 200 to 0.15 μs, for isolated molecules in solution and relate our findings for isolated molecules in solution to the spin relaxation mechanisms that are likely to be relevant in solid state systems.

  7. Single Top Quark Production at the LHC Understanding Spin

    CERN Document Server

    Mahlon, G; Mahlon, Gregory; Parke, Stephen

    2000-01-01

    We show that the single top quarks produced in the Wg-fusion channel at a proton-proton collider at a center-of-mass energy sqrt{s}=14 TeV posses a high degree of polarization in terms of a spin basis which decomposes the top quark spin in its rest frame along the direction of the spectator jet. A second useful spin basis is the eta-beamline basis, which decomposes the top quark spin along one of the two beam directions, depending on which hemisphere contains the spectator jet. We elucidate the interplay between the two- and three-body final states contributing to this production cross section in the context of determining the spin decomposition of the top quarks, and argue that the zero momentum frame helicity is undefined. We show that the usefulness of the spectator and eta-beamline spin bases is not adversely affected by the cuts required to separate the Wg-fusion signal from the background.

  8. Drones, quasi-spin or iso-spin. A comparison of many-body techniques for general spin

    International Nuclear Information System (INIS)

    McKenzie, B.J.; Stedman, G.E.

    1976-01-01

    For an effective-spin system with 2S + 1 levels there are a number of possible mappings of spin onto pseudo-fermion operators. The relative merits of three of these methods are investigated by calculating to second order the dispersion relation for coupled spin-phonon modes in crystals containing S = 1 effective spin impurities. It is found that the drone formalism quickly becomes intractable at higher spin values, as does the related quasi-spin formalism developed in contrast with the iso-spin (or Abrinkosov projection) formalism. (author)

  9. Bipolar spintronics: from spin injection to spin-controlled logic

    International Nuclear Information System (INIS)

    Zutic, Igor; Fabian, Jaroslav; Erwin, Steven C

    2007-01-01

    An impressive success of spintronic applications has been typically realized in metal-based structures which utilize magnetoresistive effects for substantial improvements in the performance of computer hard drives and magnetic random access memories. Correspondingly, the theoretical understanding of spin-polarized transport is usually limited to a metallic regime in a linear response, which, while providing a good description for data storage and magnetic memory devices, is not sufficient for signal processing and digital logic. In contrast, much less is known about possible applications of semiconductor-based spintronics and spin-polarized transport in related structures which could utilize strong intrinsic nonlinearities in current-voltage characteristics to implement spin-based logic. Here we discuss the challenges for realizing a particular class of structures in semiconductor spintronics: our proposal for bipolar spintronic devices in which carriers of both polarities (electrons and holes) contribute to spin-charge coupling. We formulate the theoretical framework for bipolar spin-polarized transport, and describe several novel effects in two- and three-terminal structures which arise from the interplay between nonequilibrium spin and equilibrium magnetization

  10. Reservation wages and starting wages

    NARCIS (Netherlands)

    van Ophem, H.; Hartog, J.; Berkhout, P.

    2011-01-01

    We analyse a unique data set that combines reservation wage and actually paid wage for a large sample of Dutch recent higher education graduates. On average, accepted wages are almost 8% higher than reservation wages, but there is no fixed proportionality. We find that the difference between

  11. Can Creativity Predict Cognitive Reserve?

    Science.gov (United States)

    Palmiero, Massimiliano; Di Giacomo, Dina; Passafiume, Domenico

    2016-01-01

    Cognitive reserve relies on the ability to effectively cope with aging and brain damage by using alternate processes to approach tasks when standard approaches are no longer available. In this study, the issue if creativity can predict cognitive reserve has been explored. Forty participants (mean age: 61 years) filled out: the Cognitive Reserve…

  12. Homoepitaxial graphene tunnel barriers for spin transport (Presentation Recording)

    Science.gov (United States)

    Friedman, Adam L.

    2015-09-01

    Tunnel barriers are key elements for both charge-and spin-based electronics, offering devices with reduced power consumption and new paradigms for information processing. Such devices require mating dissimilar materials, raising issues of heteroepitaxy, interface stability, and electronic states that severely complicate fabrication and compromise performance. Graphene is the perfect tunnel barrier. It is an insulator out-of-plane, possesses a defect-free, linear habit, and is impervious to interdiffusion. Nonetheless, true tunneling between two stacked graphene layers is not possible in environmental conditions (magnetic field, temperature, etc.) usable for electronics applications. However, two stacked graphene layers can be decoupled using chemical functionalization. Here, we demonstrate homoepitaxial tunnel barrier devices in which graphene serves as both the tunnel barrier and the high mobility transport channel. Beginning with multilayer graphene, we fluorinate or hydrogenate the top layer to decouple it from the bottom layer, so that it serves as a single monolayer tunnel barrier for both charge and spin injection into the lower graphene transport channel. We demonstrate successful tunneling by measuring non-linear IV curves, and a weakly temperature dependent zero bias resistance. We perform lateral transport of spin currents in non-local spin-valve structures and determine spin lifetimes with the non-local Hanle effect to be commensurate with previous studies (~200 ps). However, we also demonstrate the highest spin polarization efficiencies (~45%) yet measured in graphene-based spin devices [1]. [1] A.L. Friedman, et al., Homoepitaxial tunnel barriers with functionalized graphene-on-graphene for charge and spin transport, Nat. Comm. 5, 3161 (2014).

  13. Ensuring the Reliable Operation of the Power Grid: State-Based and Distributed Approaches to Scheduling Energy and Contingency Reserves

    Science.gov (United States)

    Prada, Jose Fernando

    Keeping a contingency reserve in power systems is necessary to preserve the security of real-time operations. This work studies two different approaches to the optimal allocation of energy and reserves in the day-ahead generation scheduling process. Part I presents a stochastic security-constrained unit commitment model to co-optimize energy and the locational reserves required to respond to a set of uncertain generation contingencies, using a novel state-based formulation. The model is applied in an offer-based electricity market to allocate contingency reserves throughout the power grid, in order to comply with the N-1 security criterion under transmission congestion. The objective is to minimize expected dispatch and reserve costs, together with post contingency corrective redispatch costs, modeling the probability of generation failure and associated post contingency states. The characteristics of the scheduling problem are exploited to formulate a computationally efficient method, consistent with established operational practices. We simulated the distribution of locational contingency reserves on the IEEE RTS96 system and compared the results with the conventional deterministic method. We found that assigning locational spinning reserves can guarantee an N-1 secure dispatch accounting for transmission congestion at a reasonable extra cost. The simulations also showed little value of allocating downward reserves but sizable operating savings from co-optimizing locational nonspinning reserves. Overall, the results indicate the computational tractability of the proposed method. Part II presents a distributed generation scheduling model to optimally allocate energy and spinning reserves among competing generators in a day-ahead market. The model is based on the coordination between individual generators and a market entity. The proposed method uses forecasting, augmented pricing and locational signals to induce efficient commitment of generators based on firm

  14. Design and implementation of land reservation system

    Science.gov (United States)

    Gao, Yurong; Gao, Qingqiang

    2009-10-01

    Land reservation is defined as a land management policy for insuring the government to control primary land market. It requires the government to obtain the land first, according to plan, by purchase, confiscation and exchanging, and then exploit and consolidate the land for reservation. Underlying this policy, it is possible for the government to satisfy and manipulate the needs of land for urban development. The author designs and develops "Land Reservation System for Eastern Lake Development District" (LRSELDD), which deals with the realistic land requirement problems in Wuhan Eastern Lake Development Districts. The LRSELDD utilizes modern technologies and solutions of computer science and GIS to process multiple source data related with land. Based on experiments on the system, this paper will first analyze workflow land reservation system and design the system structure based on its principles, then illustrate the approach of organization and management of spatial data, describe the system functions according to the characteristics of land reservation and consolidation finally. The system is running to serve for current work in Eastern Lake Development Districts. It is able to scientifically manage both current and planning land information, as well as the information about land supplying. We use the LRSELDD in our routine work, and with such information, decisions on land confiscation and allocation will be made wisely and scientifically.

  15. Some recent developments in spin glasses

    Indian Academy of Sciences (India)

    I give some experimental and theoretical background to spin glasses, and then discuss the nature of the phase transition in spin glasses with vector spins. Results of Monte Carlo simulations of the Heisenberg spin glass model in three dimensions are presented. A finite-size scaling analysis of the correlation length of the ...

  16. Squeezing of Collective Excitations in Spin Ensembles

    DEFF Research Database (Denmark)

    Kraglund Andersen, Christian; Mølmer, Klaus

    2012-01-01

    We analyse the possibility to create two-mode spin squeezed states of two separate spin ensembles by inverting the spins in one ensemble and allowing spin exchange between the ensembles via a near resonant cavity field. We investigate the dynamics of the system using a combination of numerical an...

  17. Phase space representations for spin23

    International Nuclear Information System (INIS)

    Polubarinov, I.V.

    1991-01-01

    General properties of spin matrices and density ones are considered for any spin s. For spin 2 3 phase space representations are constructed. Representations, similar to the Bell one, for the correlator of projections of two spins 2 3 in the singlet state are found. Quantum analogs of the Bell inequality are obtained. 14 refs

  18. Spin tunneling and manipulation in nanostructures.

    Science.gov (United States)

    Sherman, E Ya; Ban, Yue; Gulyaev, L V; Khomitsky, D V

    2012-09-01

    The results for joint effects of tunneling and spin-orbit coupling on spin dynamics in nanostructures are presented for systems with discrete and continuous spectra. We demonstrate that tunneling plays the crucial role in the spin dynamics and the abilities of spin manipulation by external electric field. This result can be important for design of nanostructures-based spintronics devices.

  19. Efficiency of free-energy calculations of spin lattices by spectral quantum algorithms

    International Nuclear Information System (INIS)

    Master, Cyrus P.; Yamaguchi, Fumiko; Yamamoto, Yoshihisa

    2003-01-01

    Ensemble quantum algorithms are well suited to calculate estimates of the energy spectra for spin-lattice systems. Based on the phase estimation algorithm, these algorithms efficiently estimate discrete Fourier coefficients of the density of states. Their efficiency in calculating the free energy per spin of general spin lattices to bounded error is examined. We find that the number of Fourier components required to bound the error in the free energy due to the broadening of the density of states scales polynomially with the number of spins in the lattice. However, the precision with which the Fourier components must be calculated is found to be an exponential function of the system size

  20. Ion Channel Conformation and Oligomerization Assessment by Site-Directed Spin Labeling and Pulsed-EPR.

    Science.gov (United States)

    Pliotas, Christos

    2017-01-01

    Mechanosensitive (MS) ion channels are multimeric integral membrane proteins that respond to increased lipid bilayer tension by opening their nonselective pores to release solutes and relieve increased cytoplasmic pressure. These systems undergo major conformational changes during gating and the elucidation of their mechanism requires a deep understanding of the interplay between lipids and proteins. Lipids are responsible for transmitting lateral tension to MS channels and therefore play a key role in obtaining a molecular-detail model for mechanosensation. Site-directed spin labeling combined with electron paramagnetic resonance (EPR) spectroscopy is a powerful spectroscopic tool in the study of proteins. The main bottleneck for its use relates to challenges associated with successful isolation of the protein of interest, introduction of paramagnetic labels on desired sites, and access to specialized instrumentation and expertise. The design of sophisticated experiments, which combine a variety of existing EPR methodologies to address a diversity of specific questions, require knowledge of the limitations and strengths, characteristic of each particular EPR method. This chapter is using the MS ion channels as paradigms and focuses on the application of different EPR techniques to ion channels, in order to investigate oligomerization, conformation, and the effect of lipids on their regulation. The methodology we followed, from the initial strategic selection of mutants and sample preparation, including protein purification, spin labeling, reconstitution into lipid mimics to the complete set-up of the pulsed-EPR experiments, is described in detail. © 2017 Elsevier Inc. All rights reserved.