astronomy

Tohru Eguchi

Tohru Eguchi is a astronomy topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Tohru Eguchi rather than just read about it. In short: Tohru Eguchi (江口徹, February 2, 1948 – January 30, 2019) was a Japanese theoretical physicist. Life and career Tohru Eguchi was a professor at the University of Tokyo, and then at the Yukawa Institute for Theoretical Physics at Kyoto University, of which he was acting director in 2009.

Key takeaways

Tohru Eguchi belongs to astronomy; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Tohru Eguchi to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Tohru Eguchi from memory before moving on to harder problems.

Reference excerpt

Tohru Eguchi (江口徹, February 2, 1948 – January 30, 2019) was a Japanese theoretical physicist.

Life and career Tohru Eguchi was a professor at the University of Tokyo, and then at the Yukawa Institute for Theoretical Physics at Kyoto University, of which he was acting director in 2009. From 2012, he was a specially-appointed professor at Rikkyo University. He dealt in particular with differential geometric methods in physics, with Superstring theory, Conformal field theory, Topological quantum field theory, Lattice gauge theory, Quantum gravity, and the Theory of Gravitation. While at SLAC in 1978, Eguchi and Andrew J. Hanson discovered an exact Euclidean instanton solution of the vacuum equations of general relativity, the Eguchi–Hanson space metric. This solution has applications, for example, in the construction of smooth compact Calabi–Yau manifolds in superstring theory. In the early 1980s, he published an influential and widely cited review article on differential geometric methods in physics with Andrew J. Hanson and Peter Gilkey. They extensively treated the physical applications of the Atiyah-Singer index theorem and related mathematical results. With Hikaru Kawai, he developed the Eguchi-Kawai model for lattice theories with an SU(N) gauge group in the limit of large N. They showed that in this limit the lattice gauge theory for an infinite lattice and unit cube are identical and that this correspondence can also be maintained in the continuum limit of the lattice. Spacetime is incorporated in this large N limit as though it were an internal degree of freedom.

Awards Eguchi shared second prize with Hanson in the 1979 Gravity Research Foundation competition. In 1984 he received the Nishina Prize, and in 2009, he received the Imperial Prize and the Prize of the Japanese Academy of Sciences.

References

Illustrations

Worked examples

Example 1 — a first encounter with Tohru Eguchi

Start with the simplest possible case. Write down what Tohru Eguchi claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In astronomy, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Tohru Eguchi before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Tohru Eguchi ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Tohru Eguchi

In research: Tohru Eguchi appears in astronomy research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Tohru Eguchi in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Tohru Eguchi is common in secondary-school and first-year university syllabi. It links to neighbouring topics 1948 births, 2019 deaths, Academic staff of Kyoto University, so understanding it makes those chapters shorter.
In everyday life: Look for Tohru Eguchi outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study Tohru Eguchi in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Tohru Eguchi means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain Tohru Eguchi out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Tohru Eguchi in simple terms?

Tohru Eguchi (江口徹, February 2, 1948 – January 30, 2019) was a Japanese theoretical physicist. Life and career Tohru Eguchi was a professor at the University of Tokyo, and then at the Yukawa Institute for Theoretical Physics at Kyoto University, of which he was acting director in 2009.

Why does Tohru Eguchi matter?

Because it connects several astronomy ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Tohru Eguchi?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Tohru Eguchi.