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Today in History – 3 February

By
Syskool
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1

1760

Sadashiv Bhau, under a large Maratha army, defeated the Nizam in War of Udgir.

Bhau was the nephew of Peshwa Baji Rao I, He played an important role in the third battle of Panipat He was the Sarsenapati of the Maratha Army. In the same battle of Panipat, he died fighting. He was the son of Chimaji Appa and Rakhmabai.

1916

Banaras Hindu University was opened under the guidance of Madan Mohan Malaviya in Varanasi, Uttar Pradesh.

It is still one of the largest residential universities in Asia with a strength of over 20,000 students. BHU is a public central university.

1925

First Electric Train started its journey from Bombay V. T. (presently known as C.S.T.) to Kurla. This train was on the Central Railway, Bombay.

The train was electrified on 1500 Volt DC. Later the electric line was first extended to Nasik’s Lagatpuri and then to Puna. Till Indian independence in 1947 around 388 km of Railway was electrified in the country.

1928

Simon Commission comes to India under Lord Irwin, after which serious rioting started on his arrival.

1988

INS Chakra was inducted into the Indian Navy when the first Soviet SSN Victor 1 class nuclear-propelled submarine and India joined the maritime nuclear powers.

1994

Akash missile launched successfully. It is a medium-range mobile surface-to-air missile defense system developed by the Defence Research and Development Organisation (DRDO), Bharat Dynamics Limited (BDL) for Missile Systems, Ordnance Factories Board and Bharat Electronics (BEL).

1995

The Transplantation of Human Organs Act, notified after 7 months of Presidential assent, becomes enforceable.

United Nations Conference on Trade and Development (UNCTAD)

By
Syskool
-
0
unctad

United Nations Conference on Trade and Development (UNCTAD) is the principal organ of the United Nations General Assembly dealing with trade, investment, and development issues. It was established in 1964 as a permanent intergovernmental body. The organization’s goals are to: “maximize the trade, investment, and development opportunities of developing countries and assist them in their efforts to integrate into the world economy on an equitable basis.

UNO declared 1960-70 as the development decade. In 1961, UNO attempted to increase the income of developing countries with the growth rate of 5% p.a. during that development decade. In July 1960, a conference of developing countries was held in Cairo which resolved to convene a world conference for this purpose. Economic and Social Council of UNO organize a World Trade and Development Conference from March 31, 1964, to July 16, 1964. A worldwide International Trade Policy was determined in this conference. Various issues related to the extension of international trade of developing countries were also discussed in that conference. The conference came to be known as UNCTAD-I.

Presently, it has become a permanent organization for promoting international trade with its headquarter at Geneva (Switzerland), Mr. Allec Irwin is its present Chairman. Generally, it has its session after four years. IMF has got the permanent representation in all its bodies. This is the reason why IMF includes all United Nations Conference on Trade and Development (UNCTAD) proposals in its policies. Its recommendations are only suggestions and no country can be compelled to accept them.

Read Also: IMF Vs World Bank  How IMF and World Bank are different?

The details are as follows:

UNCTAD I Cairo Mar 31 – June 16, 1964
UNCTAD II New Delhi Feb – March 1968
UNCTAD III Santiago (Chile) April – May 1972
UNCTAD IV Nairobi (Africa) May 1976
UNCTAD V Manila (Philippines) May 7 – June 2, 1979
UNCTAD VI Belgrade (Yugoslavia) June 6 – July 3, 1983
UNCTAD VII Geneva (Switzerland) 1987
UNCTAD VIII Cartegina DE Indias (Colombia) 1992
UNCTAD IX Midrand (Africa) April 27 – May 11, 1996
UNCTAD X Bangkok (Thailand) Feb 12 – Feb 19, 2000
UNCTAD XI Sao-Paulo (Brazil) June 13 – June 18, 2004
UNCTAD XII Accra (Ghana) April 20 – April 25, 2008
UNCTAD XIII Doha (Qatar) 21 – 26 April 2012
UNCTAD XIV Nairobi (Kenya) 17 to 22 July 2016

 

Objectives of United Nations Conference on Trade and Development

  1. To promote international trade especially with the view to accelerating the economic development of underdeveloped countries.
  2. To determine policies and principles for international trade and economic development.
  3. To propose the strategy for implementing pre-approved principles and policies.
  4. To assist Economic and Social Council of the UNO.
  5. To provide a suitable platform for trade dialogues.

Don’t Miss: Human Rights and its Historical Background

Members of United Nations Conference on Trade and Development

Though it is functioning as a permanent agency of the UNO, but its membership is fully optional. Any country may join or quit. The functions of the United Nations Conference on Trade and Development is that on democratic principles every member has only one voting right. For general disputes, the simple majority among present members but the two- third majority is needed for important issues.

Also, Read:

Important Funding Agencies of the World

The International Fund for Agricultural Development (IFAD)

Quantum Anomalous Hall Effect: Topology Without Magnetic Fields

By
Kumar Prafull
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0

Table of Contents

  1. Introduction
  2. From Hall to Quantum Hall Effects
  3. What Is the Quantum Anomalous Hall Effect?
  4. Topological Origins and Band Inversion
  5. Breaking Time-Reversal Symmetry Without Fields
  6. Chern Insulators and Berry Curvature
  7. The Haldane Model
  8. Experimental Realization in Magnetic Topological Insulators
  9. Role of Spin-Orbit Coupling and Exchange Interactions
  10. Thin Film Engineering for QAHE
  11. Quantized Hall Conductance Without Magnetic Fields
  12. Chiral Edge States and Transport Properties
  13. Temperature Dependence and Challenges
  14. Materials for QAHE
  15. Measurement Techniques and Detection
  16. QAHE in 2D Van der Waals Systems
  17. QAHE and Axion Insulators
  18. QAHE in Higher Chern Number Phases
  19. Potential Applications in Quantum Devices
  20. Conclusion

1. Introduction

The Quantum Anomalous Hall Effect (QAHE) exhibits quantized Hall conductance without an external magnetic field. It arises from internal magnetization and spin-orbit coupling in topological systems, making it a fascinating frontier of condensed matter physics.

2. From Hall to Quantum Hall Effects

The classical Hall effect arises from Lorentz forces. The Quantum Hall Effect (QHE) shows quantized conductance in 2D electron gases under strong magnetic fields. QAHE eliminates the need for such fields, retaining quantization via intrinsic magnetic order.

3. What Is the Quantum Anomalous Hall Effect?

In QAHE, a 2D system exhibits a Hall resistance of:
\[
R_H = rac{h}{Ce^2}
\]
where \( C \) is an integer Chern number, even without applying a magnetic field, due to internal time-reversal symmetry (TRS) breaking.

4. Topological Origins and Band Inversion

QAHE results from band inversion caused by spin-orbit coupling (SOC) and magnetization, creating a nontrivial topology in the electronic band structure. The topological invariant is the Chern number.

5. Breaking Time-Reversal Symmetry Without Fields

Unlike QHE which uses external B-fields, QAHE employs magnetic dopants (e.g., Cr or V in topological insulators) to break TRS internally, inducing spontaneous magnetization.

6. Chern Insulators and Berry Curvature

QAHE systems are Chern insulators. The integral of the Berry curvature over the Brillouin zone yields a nonzero Chern number, responsible for the quantized transverse conductance.

7. The Haldane Model

Proposed in 1988, the Haldane model is a theoretical prototype of QAHE. It demonstrates that complex next-nearest-neighbor hopping on a honeycomb lattice can induce a quantized Hall effect without net magnetic flux.

8. Experimental Realization in Magnetic Topological Insulators

The first experimental QAHE was observed in Cr-doped (Bi,Sb)₂Te₃ thin films at millikelvin temperatures. Key features:

  • Quantized Hall resistance
  • Vanishing longitudinal resistance
  • Hysteresis in magnetization

9. Role of Spin-Orbit Coupling and Exchange Interactions

SOC induces band inversion, while magnetic dopants provide exchange fields. The interplay creates a topological gap and lifts degeneracy in surface states.

10. Thin Film Engineering for QAHE

Thin film growth techniques such as Molecular Beam Epitaxy (MBE) allow control over thickness, doping concentration, and interface quality—crucial for QAHE observation.

11. Quantized Hall Conductance Without Magnetic Fields

At low temperatures, conductance becomes quantized:
\[
\sigma_{xy} = C \cdot rac{e^2}{h}, \quad \sigma_{xx} o 0
\]
demonstrating dissipationless edge transport in the absence of magnetic fields.

12. Chiral Edge States and Transport Properties

QAHE supports one-way (chiral) edge modes immune to backscattering. These states persist even when the bulk becomes insulating, enabling robust quantum transport.

13. Temperature Dependence and Challenges

Current realizations require ultralow temperatures (~30 mK). Raising the QAHE temperature to accessible levels remains a major challenge due to magnetic disorder and small gap sizes.

14. Materials for QAHE

Promising systems include:

  • Cr/V-doped Bi₂Se₃ and (Bi,Sb)₂Te₃
  • MnBi₂Te₄ (intrinsic magnetic TI)
  • Magnetic van der Waals heterostructures

15. Measurement Techniques and Detection

QAHE is characterized using:

  • Four-probe magnetotransport
  • Gate-tunable Hall bar measurements
  • SQUID magnetometry and Kerr rotation for magnetic order

16. QAHE in 2D Van der Waals Systems

Layered magnetic TIs and engineered heterostructures offer QAHE platforms with better tunability. Interfacing with graphene and hBN opens new control pathways.

17. QAHE and Axion Insulators

Multilayer QAHE systems with opposing magnetizations can realize axion insulator states. These exhibit topological magnetoelectric effects and open pathways to detect axionic responses.

18. QAHE in Higher Chern Number Phases

QAHE can exhibit \( C > 1 \) in multilayer systems or engineered superlattices. These phases have multiple chiral edge channels and richer transport behavior.

19. Potential Applications in Quantum Devices

  • Low-power interconnects and logic gates
  • Topological memory elements
  • Fault-tolerant quantum circuits using chiral edge states
  • Magnetoelectric and spintronic applications

20. Conclusion

The Quantum Anomalous Hall Effect bridges topology, magnetism, and quantum electronics. Realizing QAHE at higher temperatures and in versatile materials remains a grand goal, with implications spanning fundamental physics to quantum device engineering.

.

Today in History – 2 February

By
Syskool
-
0

1788

Pitt’s Regulatory Act was introduced to To modify the Indian Administration and put further controls on Government of British India after the 1784 Bill.

Earlier, in 1784, Pitt’s India Act was was enacted under the name East India Company Act 1784. This act came after the Regulating Act of 1773, it brought the company’s rule in India under government’s control by appointing the Board of Control and gave provision of joint government of British India by both Company and Crown but the apex authority remained in the hands of British Government.

1814

Calcutta Museum was established. It was a part of the Asiatic Society at a suggestion of a Danish surgeon Dr. Nathaniel Wallich, who was its first Director also.

1835

Thomas Babington Macaulay westernises education in India. English is made official government and court language and as medium of instruction.

1949

Press Trust of India’ was established.

1957 and 1958

In 1987 for the first time Indira Gandhi was elected the president Congress Party. In 1958 again she did it but this time thereby Congress faced an spilt, because of her leftist inclination and congress was truing into more socialist. Under C. Rajagopalachari they formed Swantantra Party.

1977

Jagjivan Ram, Cabinet member of 30 years, resigns to protest emergency rule causing minor split in Congress party.

1978

Mahakavi G. Shankar Kurup, Malayalam poet, the first receipent of “Gyanpeeth Puraskar (Award), and many other awards, passed away.

2006

Mahatma Gandhi National Rural Employment Guarantee Act, 2005 earlier know as NREGA implemented. It was flagged off from Bandlapalli village of Anantpur in Andhra Pradesh on this day.

International Monetary Fund – Members and Voting Rights

By
Syskool
-
0
imf member international monetary fund

International Monetary Fund (IMF) is an international organization, established on December 27, 1945, in Washington on the recommendations of Bretton Woods Conference. But it started its operation on March 1, 1947. At present 189 nations are members of the International Monetary Fund. Nauru became the newest member in April 2016.

After Dominique Strauss-Kahn, Christine Lagard had been made as Managing Director of IMF on July 5, 2011. She is still serving as 11th MD of International Monetary Fund.

Objectives of International Monetary Fund
According to Article of Agreement of the IMF, its main objectives are as follows:

(1) To promote international monetary co-operation

(2) To ensure balanced international trade

(3) To ensure exchange rate stability

(4) To eliminate or to minimize exchange restrictions by promoting the system of multilateral payments

(5) To grant economic assistance to member countries for eliminating the adverse imbalance in balance payments.To minimize imbalance in quantum and duration of international trade

(6) To minimize imbalance in quantum and duration of international trade

Constitution, Membership, and Capital of International Monetary Fund

International Monetary Fund is controlled and managed by a board of Governors. Each member country nominates a Governor. All the nominated Governors make a board of governors. Each country also nominates an alternate Governor who casts his vote in the absence of the Governor. Each Governor is allotted a number of votes which is determined by the quota allotted to the respective country in the capital of IMF. Each Governor has got the right of 250 votes on the basis of membership and one additional vote for each SDR 1,00,000 of quota. The additional of these two types of votes becomes the actual voting right of the member country. It clearly indicates that the voting right depends on the quantum of the quota of a particular country with IMF. This is the reason why the rich and industrialised countries got the higher voting rights due to their higher quotas. with theInternational Monetary Fund.

Read Also: The Governor: Appointment, Functions, and Powers

The main source of International Monetary Fund resources is the quota allotted to the member countries. Till 1971, all the amounts of quotas and the assistance provided were denominated in US dollar, but since December 1971, all the quotas and transactions are expressed in SDR (Special Drawing Right) which is also known as Paper Gold. In 1971, one SDR was assumed equivalent to 1 dollar but due to the subsequent decline in dollar value,  SDR 1 became equivalent to $1.585 by the end of April 1995. Since January 1, 1981, the value of SDR is being determined by the basket  of currency of 5 largest exporting member countries: US dollar, Deutsche Mark, Yen, Franc, and Pound Sterling.

In 1991, the weight to these 5 currencies in SDR price determination was as follows:

American Dollar 40 %
German Franc 21 %
Japanese Yen 17 %
British Pound 11 %
French Franc 11 %

The currency value of SDR is determined by the IMF each day by summarising the value in US dollars, based on the market exchange rates of a basket of fine currencies.

The IMF’s financial year is from 1 May to 30 April. IMF lends to various member countries in the form of various facilities (Extended Fund Facility, Standby Facility, Contingent Credit Lines, Compensatory Facility etc.) designed to serve a specific purpose, but essentially aimed at a balance of payments stabilisation or meeting the emergent foreign exchange needs. The poor countries are also helped by funding from Poverty Reduction and Growth Facility. As on June 2004, the IMF was lending to 13 members in the from of standby facility, to two members under Extended Arrangements and 38 poor countries under poverty Reduction and Growth Facility.

The quota allotted by the IMF to each member has to be deposited partly in their own currency and remainder in the form of foreign exchange.

Read Also: IBSA Dialogue Forum: A New Initiative of Developing Countries

India’s 8th Place in International Monetary Fund General Quota

After the review of IMF’s General Quota, India’s quota has been raised to 1311.44 crore SDR. (to understand today on 15/10/2017 1 SDR = $ 1.42 = Rs 91.52). This quota hike has raised India’s vote share 2.79%.
India has been placed at 8th place in IMF’s General Quota. The USA remains in biggest quota holder despite its quota share of 17.68%.

Country Quota
USA 17.68%
Japan 6.56%
China 6.49%
Germany 5.67%
France 4.29%
UK 4.29%
Country Quota
Italy 3.21%
India 2.79%
Russia 2.75%
Brazil 2.35%
Canada 2.35%
Saudi Arabia 2.13%

India and International Monetary Fund

International Monetary Fund has played an important role in Indian economy. IMF has provided economic assistance from time to time to India and has also provided appropriate consultancy in the determination of various policies in the country. India is the founder member of IMF. The finance minster is ex-officio governor in IMF board of Governors. Till 1970, India was among the first five-nation highest quota with IMF and due to this status, India was allotted a permanent Place in executive Board of Directors.

IMF Financial Transactions Plan

India participates in FTP of the IMF from 2002. 43 countries, including India, now participate in FTP. By participation in FTP, India is allowing IMF to encash its rupee holding as a part of our quota contribution for hard currency which is then lent to other member countries who are debtors to the IMF.

Don’t Miss: Foreign Trade Policy (FTP) 2015

In July India and IMF joint training program at then National Institute of Banking Management, Pune was established. The training program will provide policy-oriented training in economics and related operational fields to Indian officials and officials of countries in South Asia and East Africa. The first training program was held during July 2006. The RBI is a nodal body to co-ordinate the training program with the International Monetary Fund.

Enhanced Structural Adjustment Facility

Enhanced Structural Adjustment Facility (ESAF) was established in 1987 with an amount of SDR 6 billion to help the low-income countries with heavy debt burdens in the difficult external environment and implement comprehensive macro-economic and structural policy program aiming at strengthening their balance of payments position and fostering growth. India contributes as donations to Subsidy Account and made a commitment to provide grant contribution to the extent of US $ 1 million per year over 15 years for a total of US $ 15 million.

Don’t Miss:

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