PH 3124 :  Quantum Mechanics I
(August-December, 2024)

This is a first course on non-relativistic quantum mechanics.

Course contents :
Books :

NOTE 1 : The first two books in this list can be downloaded legally within IISER Pune.
NOTE 2 : Ref 1, 2, 3 in the updates (given below) refer to these text books.
  1. Principles of quantum mechanics by R. Shankar
  2. Quantum mechanics : An Introduction by Walter Greiner
  3. Introduction to quantum mechanics by David Griffiths
Evaulation :
Office hours :

Announcements :
🖈 Aug 14, 2024 : Quiz-1 will be held on 5.9.2024 during 9 to 10 AM.
Everything taught in class until 27.8.2024 will be part of this test. Harmonic oscillator not part of the test.

🖈 Sep 12, 2024 : Quiz-1 :Question paper and Solution

🖈 Sep 12, 2024 : For mid-semester exam, everything taught in class until 12.9.2024 (lectures 1 to 16) will be part of the exam.

🖈 Oct 10, 2024 : Quiz-2 will be held on 7.11.2024 during 9 to 10 AM. Everything covered in lectures 17 to 25 will be part of this quiz.

🖈 Oct 22, 2024 : Midsem exam : Question paper and Solution

🖈 Nov 10, 2024 : Quiz 2 : Question paper and Solution

🖈 Nov 18, 2024 : End-sem exam : Everything covered in lectures 1 to 34 will be part of this exam. However, 75% of the questions will be from the part taught after mid-sem exam (lectures 17 to 34).

🖈 Dec 6, 2024 : Endsem exam : Question paper and Solution


Assignments / problem sheets :

🖈 Aug 26, 2024 : Assignment-1 (Try out these sample problems)
🖈 Nov 4, 2024 : Assignment-2 (Try out these sample problems)
🖈 Nov 5, 2024 : Sample problem set-1 with solutions (By Bharathi Kannan)
🖈 Nov 10, 2024 : Sample problem set-2 with solutions


COURSE UPDATES :
NOTE 1 : Course updates will appear here.
NOTE 2 : Ref 1, 2, 3 refer to the text book list given above.
NOTE 3 : 🟤 Brown circle indicates that the content is for extra reading and not necessary for this course.


║ 18.11.2024 ║ Lecture 34 ║
Problems
Some problems with solution on spin-1/2 particles

║ 14.11.2024 ║ Lecture 33 ║
Spin
⯈ Pauli matrices and their properties, (See Sec 14.3 in Ref 1)
⯈ Spin operators about arbitrary direction, (Sec 14.3 in Ref 1)
⯈ Representing an arbitrary \( 2 \times 2 \) matrix in terms of Pauli matrices, (Sec 14.3 in Ref 1, and see this example problem)
Rotation operators for spins (See sec 14.3 in Ref 1)
🟤 (Extra reading, not mandatory for the course) Quantum particles are not spinning: historical notes on spin.

║ 12.11.2024 ║ Lecture 32 ║
Spin
⯈ Stern-Gerlach experiment,
electron spin,
⯈ Spin operators and algebra (See sec 14.3 in Ref 1)
⯈ Pauli spin matrices (See sec 14.3 in Ref 1, OR sec 4.1.1 in Ref 3)
🟤 Lasting impact of Stern-Gerlach experiment.
🟤 Stern-Gerlach : How a bad cigar changed atomic physics.
🟤 Do your own Stern-Gerlach experiment here.

║ 11.11.2024 ║ Lecture 31 ║
Solving Hydrogen atom problem
⯈ Solution to radial Schrodinger equation for Hydrogen atom potential : eigenstates (See sec 13.1 in Ref 1, OR sec 4.2 in Ref 3)

║ 7.11.2024 ║ Quiz-2 ║
║ 5.11.2024 ║ Lecture 30 ║
Solving Hydrogen atom problem
⯈ Solution to radial Schrodinger equation for Hydrogen atom potential : energy eigenvalues (See sec 13.1 in Ref 1, OR sec 4.2 in Ref 3)

║ 4.11.2024 ║ Lecture 29 ║
Solution to \( \theta,\phi \) part of Schrodinger equation
Solution to \( \theta,\phi \) part of Schrodinger equation (See sec 4.1 in Ref 3)
Visualising spherical harmonics
One more site for plotting spherical harmonics

║ 29.10.2024 ║ Lecture 28 ║
Angular momentum algebra
⯈ Explicit matrix forms for \( J_x, J_y, J_z, J_+, J_- \) and \( J^2 \). (See sec 12.5 in Ref 1)
Spherical polar coordinates
Schrodinger equation in spherical coordinates
🟤 (Extra reading, but not necessary for the course) Orbital angular momentum (OAM) of photons
🟤 Quantum computing using OAM of a single photon   (J. Opt. 13 064022 (2011)).

║ 28.10.2024 ║ Lecture 27 ║
Angular momentum algebra and operators
⯈ Solution to eigenvalue problem of \( L^2 \) and \( L_z \) (See sec 12.5 in Ref 1)

║ 24.10.2024 ║ Lecture 26 ║
Dealing with angular momentum in three dimensions
⯈ Angular momentum in three-dimensions (See sec 12.4 in Ref 1)
Deriving angular momentum commutators
Angular momentum commutators

║ 22.10.2024 ║ Lecture 25 ║
Two-dimensional harmonic oscillator
Solving 2D oscillator (See also exercise 12.3.7 in Section 12.4 of Ref 1)
A little more detailed solution to 2D oscillator
⯈ Note : Most of the standard 2D rotationally invariant problems can be solved in a similar way as the 2D harmonic oscillator.
Some pictures of 2D oscillator eigenstates (make your own eigenstate)

║ 21.10.2024 ║ Lecture 24 ║
Cartesian to polar coordinates
Cartesian to polar coordinates in two-dimensions
Laplacian operator in polar coordinates in 2D

║ 17.10.2024 ║ Lecture 23 ║
Solving rotationally invariant problems : \(z\)-component of angular momentum
Solving for eigenstates of \(L_z\) operator (see Section 12.3 in Ref 1)
A sample problem (see Section 12.3 in Ref 1)
⯈ Consistency checks of composition of rotation and translation operations (see end of Sec 12.2 in Ref 1)

║ 15.10.2024 ║ Lecture 22 ║
Symmetries :
⯈ Rotational symmetry (see Sections 12.2 in Ref 1)
⯈ Invariance under rotation (see Sections 12.2 in Ref 1)

║ 14.10.2024 ║ Lecture 21 ║
Symmetries :
⯈ Parity symmetry (see Sections 11.4 in Ref 1)
⯈ Time reversal invariance (see Sections 11.5 in Ref 1)
⯈ Generalising space translation to two-dimensions (Sec 12.1 in Ref 1)

║ 10.10.2024 ║ Lecture 20 ║
Symmetries :
⯈ space and time translation symmetry (see Sections 11.2 and 11.3 in Ref 1)
⯈ Parity symmetry (see Sections 11.4 in Ref 1)

║ 8.10.2024 ║ Lecture 19 ║
Symmetries :
⯈ Space translation symmetry in quantum systems (see Sec 11.1 and 11.2 in Ref 1)

║ 7.10.2024 ║ Lecture 18 ║
Dirac delta potential :
⯈ Dirac delta potential (scattering potential) (see Sec 2.5 in Ref 3)
🟤 Optical frequency combs (Combs are a series of delta functions)

║ 3.10.2024 ║ Lecture 17 ║
Dirac delta function and Dirac delta function potential :
Dirac delta function
An easy to read article on Dirac delta function
⯈ Dirac delta function potential [bound states] (see Sec 2.5 in Ref 3)
🟤 Extra reading (but not necessary for the course) : History of Dirac delta function

║ 12.9.2024 ║ Lecture 16 ║
Minimum uncertainty wavepacket and applications of uncertainty principle :
⯈ Applications of uncertainty relation (See sec 9.3 and 9.4 in Ref 1)
⯈ Consequences of commuting and non-commuting observables
⯈ Time-dependent Schrodinger equation and time evolution of states

║ 10.9.2024 ║ Lecture 15 ║
Uncertainty principle and relation :
⯈ Uncertainty relation for non-commuting variables (See sec 9.1 and 9.2 in Ref 1)

║ 3.9.2024 ║ Lecture 14 ║
Harmonic oscillator : Evaluating matrix elements of operators, comparison with classical
⯈ Evaluation of matrix elements (See sec 7.4 in Ref 1)
⯈ Comparison with classical probability (See sec 7.4 in Ref 1)
⯈ Computing eigenstates in position basis (See sec 7.5 in Ref 1)

║ 2.9.2024 ║ Lecture 13 ║
Harmonic oscillator : raising and lowering operators, solution in energy basis
⯈ Solution in energy basis using raising/lowering operators (See sec 7.4 in Ref 1)

║ 29.8.2024 ║ Lecture 12 ║
Harmonic oscillator : energy levels and eigenfunctions
⯈ Deriving harmonic oscillator solution (See sec 7.3 in Ref 1)

║ 27.8.2024 ║ Lecture 11 ║
Ehrenfest theorem, Commutator, Harmonic oscillator
⯈ Ehrenfest theorem and conditions under which it is valid (Chapter 6 in Ref 1)
⯈ Harmonic oscillator (See sec 7.3 in Ref 1)
⯈ Commutators (See sec 7.3 in Ref 1),
Evaluation of position-momentum commutator

║ 26.8.2024 ║ Lecture 10 ║
Quantum tunnelling and its applications, Ehrenfest theorem, commutator
See tunnelling applications: radioactive decay and STM
⯈ Ehrenfest theorem (See Chapter 6 in Ref 1).
🟤 Extra reading (but not necessary for the course) : Is quantum tunnelling faster than light ?


🟤 Extra reading (but not necessary for the course) : The future of semiconductor industry

║ 22.8.2024 ║ Lecture 9 ║
Completeness of eigenstates of infinite well, solution to step potential, potential barrier problem
⯈ Completeness of eigenstates (see (4) in sec 2.2 of Ref 3). This is a general property, not just of eigenstates of infinite well system.
⯈ Step potential in one-dimension (Sec 5.4 in Ref 1).
Potential barrier in one-dimension
║ 20.8.2024 ║ Lecture 8 ║
General properties of one-dimensional quantum systems
⯈ No degeneracy in 1D quantum systems (see sec 5.6 in Ref 1), symmetry properties, orthonormal eigenstates.
⯈ Probability current density (See sec 5.3 in Ref 1)

║ 19.8.2024 ║ Lecture 7 ║
Infinite square well potential, its eigenvalues and eigenfunctions
⯈ Infinite well problem (see Sec 5.2 in Ref 1 given above)
⯈ Classical infinite well problem; comparing with quantum results. Correspondence principle.

║ 13.8.2024 ║ Lecture 6 ║
Hermitian operator and its properties, orthogonal eigenfunctions, completeness relation, solving the free particle Schrodinger equation, momentum eigenfunction
⯈ Hermitian operators and properties (see Sec 3.2 and 3.3 of Ref 3 given above)
⯈ Momentum eigenfunctions (see Sec 3.3 of Ref 3)
Free particle solution in quantum mechanics

║ 12.8.2024 ║ Lecture 5 ║
Postulates of quantum mechanics, Schrodinger equation, real eigenvalues.
⯈ Postulates of quantum mechanics [measurement postulate and time-evolution]
(See chapter 4 of Ref 1 listed above)
⯈ Time-dependent and time-independent Schrodinger equation
⯈ Hermitian operator and real eigenvalues
🟤 Extra reading (but not necessary for the course) : Is the Schrodinger equation true ?

║ 8.8.2024 ║ Lecture 4 ║
Postulates of quantum mechanics, Hilbert space, Bra-ket notation, operators, average value of operators, states and operators in different representations.
Defining Hilbert space
Bra-ket notation for starters
Bra-ket notation and postulates (pages 1-6)
Class notes on momentum operator
║ 6.8.2024 ║ Lecture 3 ║
phase and group velocity of DeBroglie wave, plane waves, Davisson-Germer experiment, Born's interpretation, superposition principle, Postulates of quantum mechanics
⯈ Phase and group velocity of DeBroglie waves (See Section 3.1 of Ref 2 given above)

║ 5.8.2024 ║ Lecture 2 ║
Wave particle duality, Double-slit experiment, De Broglie waves and its consequences

Actual double-slit experiment with electrons (Courtesy : Hitachi Co., 1989)


🟤 See also : The accompanying paper on this double-slit experiment
║ 1.8.2024 ║ Lecture 1 ║
Brief review of classical mechanics, motivations for a theoretical framework beyond classical physics
🟤 Some historical notes on origins of quantum theory


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