5.It was this element of chance, or randomness, that so disturbed Einstein.
6.It was Einstein’s paper that showed that one could directly observe individual quanta.
7.It was only in 1925 that the full implications of the photoelectric effect were realized.
Exercise 3 (do it yourself)
Translate the sentences, then compare your variant with the original sentences and make corrections, if any.
1.Уравнения общей теории относительности соотносят кривизну пространства-времени с распределением массы и энергии.
2.Известно, что Большой взрыв произошел 15 миллиардов лет тому назад.
3.Квантовая механика считается самым глубоким знанием, известным науке.
4.Было установлено, что свет испускается дискретными количествами энергии определенного размера.
5.Теорию относительности считают классической теорией, так как она не включает в себя принцип неопределенности.
UNIT 10
THE QUANTUM THEORY
PRE-READING TASK Study some grammar points. I. Would
a. We use would to talk about the natural course and behavior of things and events as a result of some action. It is the less definite form of will.
Study the sentence.
If the electrons are in orbit around the nucleus, electromagnetic waves would carry away energy and would cause the electrons to spiral into the nucleus.
− 126 −
b. We use would if we imagine the situation. We can also use could = would be able to
Study the sentence.
In this state the electron couldn’t radiate energy in the form of electromagnetic waves because there would be no lower energy state.
II. For – phrase
We use for + N + to V to talk about the purpose of doing something.
Study the sentences.
1.There would be no lower state for the electron to go to.
2.Quantum theory can be formulated as a “sum over histories.” The idea is that every particle has every possible path, or history, in spacetime. For this idea to work, one has to consider histories that take place in imaginary rather than in the real time.
3.For the idea to be formulated, it has to contain the concept of imaginary time.
Give the Russian correspondence:
the very small (the smallest), that is (that is to say), continuously (ant. discretely), at least (as a minimum), instead (rather), both …… and, in the form of
THE HEISENBERG UNCERTAINTY PRINCIPLE
AND THE MODEL OF THE ATOM
Study the passage. Mind the underlined grammar.
The general relativity theory and the Maxwell theory of electrodynamics are classical theories; that is, they involve continuously variable quantities that can, in principle at least, be measured to arbitrary accuracy. However, a problem arose when scientists tried to use such theories to construct a model of the atom.
It was discovered that the atom consists of a small, positively charged nucleus surrounded by a cloud of negatively charged electrons. The natural assumption was that the electrons were in orbit around the nucleus as the earth is in orbit around the sun. But the classical theory predicts that the electrons would radiate electromagnetic waves. These waves would carry away energy and would cause the electrons to spiral into the nucleus, producing the collapse of the atom.
− 127 −
This problem was overcome by the discovery of the quantum theory, which is the greatest achievement in theoretical physics in last century. The basic postulate of this theory is the Heisenberg uncertainty principle, which states that certain pairs of quantities, such as the position and momentum of a particle, cannot be measured simultaneously with arbitrary accuracy. In the case of the atom, this meant that in its lower energy state the electron couldn’t be at rest in the nucleus because, in that case, its position would also be exactly defined (at the nucleus) and its velocity would also be exactly defined (to be zero). Instead, both position and velocity would have to be smeared out with some probability distribution around the nucleus. In this state the electron could not radiate energy in the form of electromagnetic waves because there would be no lower energy state for it to go to.
Stephen Hawking
Vocabulary Notes
1.arbitrary – approximate – not exact – random
2.an assumption – if you make an assumption, you say that something is true, although you have no proof – an idea
3.to overcome a problem – to solve it
4. simultaneously – at the same time
POST-READING TASK
(To be done at home in writing)
I. Write a digest of the passage covering the below points:
1.Formulate the problem, which arose when one tried to use classical theories to construct the model of the atom.
2.Say how the problem was overcome.
3.Characterize the importance of the quantum theory.
4.The application of the quantum theory for the interpretation of the structure of the atom.
II. Draw the model of the atom and be ready to speak about the difference in its interpretation in terms of the classical theory and the quantum theory.
− 128 −
CLASS EXERCISES
Exercise 1 (in groups) Checking up understanding
1 What quantities does any classical theory involve?
2.What is a continuously variable quantity?
3.What does the atom consist of?
4.How would the electron behave in terms of the classical theory?
5.What is the greatest achievement in theoretical physics in last cen-
tury?
6.What is the basic postulate of the quantum theory?
7.What does the Heisenberg uncertainty principle state?
8.How would the electron behave in terms of the quantum theory?
Exercise 2 (do it yourself)
Translate the sentences, then compare your variant with the original sentences and make corrections, if any.
1.Общая теория относительности – классическая теория.
2.Теория электродинамики Максвелла – классическая теория.
3.Атом состоит из маленького положительного заряженного ядра, окружённого облаком отрицательно заряженных электронов.
4.Электроны находятся на орбите вокруг ядра, также как земля находится на орбите вокруг солнца.
5.Открытие квантовой теории является величайшим достижением теоретической физики прошлого века.
6.Основным постулатом квантовой теории является принцип неопределенности Гейзенберга, согласно которому нельзя одновременно измерить и положение частицы, и ее импульс.
Exercise 3 (in groups) Discussion
1 “The interpretation of the model of the atom in terms of the classical theory.”
2 “The interpretation of the atom in terms of the quantum theory.”
Each student gives contribution to the discussion. The audience is asking questions.
− 129 −
UNIT 11
QUANTUM MECHANICS
“Quantum mechanics is the deepest knowledge known to science. It describes the activity of subatomic particles and deals with very small scales.”
David Deutsch
PREREADING TASK
Give Russian correspondence:
to bring about (to cause), a number of (a range of, a set of) no longer (no more), once (as soon as), in some sense (true according to one of the interpretations), for instance (for example), the more … the more, neither …. nor, particularly (especially), it turns out, in terms of (in a particular language), any
QUANTUM COMPUTATION
Interview with Dr. David Deutsch, a theoretical physicist of the Centre for Quantum Computation at the University of Oxford
−How did you start working on quantum theory?
−Throughout my research career I have been interested in the most fundamental issues. I got into quantum mechanics because it is the deepest knowledge known to science. I did various kinds of work on quantum field theory, in the hope of making progress on quantum gravity. I worked on quantum measurement theory and so became an advocate of the many-universe interpretation. I saw there was a need to extend the idea of Alan Turing of a universal computer by using quantummechanical physics. And I did that: I proposed the universal quantum computer and proved it was universal. I showed it had properties that no existing computer had.
−That raises two questions. First, how do you define fundamen-
tal?
−A fundamental idea is the one which is needed in the understanding of many other ideas. For instance, the laws of thermodynamics are fundamental laws. You don’t just need them to understand how steam
−130 −