A Capella Science – Bohemian Gravity!

This video has gone viral in less than a month. Quite strange, as it does not show Miley Cyrus’ latest stravaganza and there is no funny cat on it either. It is just String theory, you know…

And here, the lyrics:

Is string theory right?
Is it just fantasy?
Caught in the landscape,
Out of touch with reality
On S5 or T*S3

Space is a pure void
Why should it be stringy? 
Because it’s quantum not classical
Any way you quantize
You’ll encounter infinity
You see

Must interact
Via paths we understand
Using Feynman diagrams
Often, they will just rebound
But now and then they go another way
A quantum
Infinities will make you cry
Unless you can renormalize your model
Of baryons, fermions
And all other states of matter

Curved space:
The graviton
Can be thought of as a field
But these infinities are real
In a many-body
Loop diagram
Our results diverge no matter what we do…
A Quantum Soup (any way you quantize)
Kiss your fields goodbye
Guess Einstein’s theory wasn’t complete at all!

I see extended 1-D objects with no mass
What’s their use? What’s their use? Can they give us quark plasma?
What to minimize?
What functional describes this
Nambu-Goto! (Nambu-Goto)
Nambu-Goto! (Nambu-Goto)
How to quantize I don’t know
I’m just a worldsheet, please minimize me
He’s just a worldsheet from a string theory
Reperametrized by a Weyl symmetry!

Fermi, Bose, open, closed, orientable?
Modes! They become particles (particles!)
They become particles (particles!)
They become particles (particles!)
Become particles (particles!)
Become particles (many many many many particle…)
Modes modes modes modes modes modes modes!
Oh mamma mia mamma mia,
Such a sea of particles!
A tachyon, with a dilaton and gravity-vity-VITY

(rock out!)

Now we need ten dimensions and I’ll tell you why
(anomaly cancellation!)
So to get down to 4D we compactify!
Oh, Kahler!
(Kahler manifold)
Manifolds must be Kahler!
(Complex Reimannian symplectic form)
If we wanna preserve
Any of our super-symmetry

(Superstrings of type I, IIa and IIb)
(Heterotic O and Heterotic E)
(All are one through S and T duality)
(Thank you Ed Witten for that superstring revolution and your new M-theory!)

(Type IIB String!)
Dual! Dual!
(In the AdS/CFT)

Molecules and atoms
Light and energy
Time and space and matter
All from one united

Any way you quantize…


Note: Lyrics and arrangement by Tim Blais and A Capella Science
Original music by QueenLyrics and arrangement by Tim Blais and A Capella Science – Original music by Queen

You can even buy the track on iTunes, here.


Historical 1927 Solvay International Conference (colourized)

Historical 1927 Solvay International Conference (colourized)

October 1927 Fifth Solvay International Conference on Electrons and Photons. Review the names… OMG!

Baths and Quarks: Solitons explained

David Tong again in my humble blog. This time, trying to explain what the solitons are. Directly extracted from YouTube’s sinopsis of the video:

In ‘Baths and Quarks‘, theoretical physics expert David Tong explains solitons and their effect on quarks and protons. ‘Solitons‘ — solitary waves which can be seen as bubble rings in the bath — make it impossible for quarks and protons to be separated, thus holding together the universe, he says. “Baths would be so much more relaxing if they weren’t so interesting. Bubble rings – there’s something strange and unnatural about these objects – so structural where you wouldn’t expect to see structure. When I get out of the bath and pull the plug, there’s a world of water that drains away – a vortex – it’s very similar to the bubble rings, and objects like these may just hold the key to one of the most important problems in particle physics [relating to quarks and protons]. My name is David Tong. My job is to understand the beautiful things that I see in the world around me. But to describe them properly, I have to understand them in the language in which nature is written.

A short definition from Wikipedia:

soliton is a self-reinforcing solitary wave (a wave packet or pulse) that maintains its shape while it travels at constant speed.


Physics rulez, don’t you think so?


The Feynman Lectures on Physics

One entry just to note down a link to The Feynman Lectures on Physics, a website by Caltech that honors the three books written by Richard P. Feynman, Robert B. Leighton and Matthew Sands, based on the introductory Physics course taught by Feynman, father of QED (and one of my favorite physicist of all time) at Caltech from 1961-63.

At the moment, the first volume (“mainly mechanics, radiation and heat“) is completely available online, for free.

I’ll keep on visiting its website from time to time. Love it!

The Feynman Lectures On Physics

The Feynman Lectures On Physics

Using Cosmology to Establish the Quantization of Gravity

A short article that I’ve read today (via @seanmcarroll).

arXiv:1309.5343 [hep-th]

Title: “Using Cosmology to Establish the Quantization of Gravity”

Authors: Lawrence M. KraussFrank Wilczek

Here is the abstract:

While many aspects of general relativity have been tested, and general principles of quantum dynamics demand its quantization, there is no direct evidence for that. It has been argued that development of detectors sensitive to individual gravitons is unlikely, and perhaps impossible. We argue here, however, that measurement of polarization of the Cosmic Microwave Background due to a long wavelength stochastic background of gravitational waves from Inflation in the Early Universe would firmly establish the quantization of gravity.

MITx: 8.01x Classical Mechanics (through edX.org)

MOOCs, MOOCs, MOOCs… I love MOOCs or massive open online courses. At the moment I’ve been quite aware of Coursera‘s offer but edX.org is also awesome. What a surprise, a course in Classical Mechanics by the MIT and taught by Professor Walter Lewin has recently started, almost a couple of weeks ago. What a pity, I’m not sure if I will follow the whole course, as I’m already a late with “homework 1” and I won’t be graded if I try to do the exercises, but I think I’ll watch the videos and some readings as a refresher.

I had heard of Prof. Lewin’s original way of explaining Physics and his love for this subject, but this will be my first time in one of his classes. In a short video I’ve just seen he states that life won’t be the same, I’ll watch the world in a different way after following the course, so with a promise like this it is an “obligation” for me to follow the course.

Here is the link to the course: MITx: 8.01x Classical Mechanics

Course’s syllabus:

Lecture 1: Powers of Ten – Units – Dimensions – Measurements – Uncertainties – Dimensional Analysis – Scaling Arguments
Lecture 2: 1D Kinematics – Speed – Velocity – Acceleration
Lecture 3: Vectors – Dot Products – Cross Products – 3D Kinematics
Lecture 4: 3D Kinematics – Free Falling Reference Frames
Lecture 5: Circular Motion – Centrifuges Moving – Reference Frames – Perceived Gravity
Lecture 6: Newton’s Laws
Lecture 7: Weight – Perceived Gravity – Weightlessness Free Fall – Zero Gravity in Orbit (Misnomer)
Lecture 8: Friction
Lecture 9: Exam 1 review
Lecture 10: Hooke’s Law – Springs – Simple Harmonic Motion – Pendulum – Small Angle Approximation
Lecture 11: Work – Kinetic Energy – Potential Energy – Conservative Forces – Conservation of Mechanical Energy – Newton’s Universal Law of Gravitation
Lecture 12: Non-Conservative Forces – Resistive Forces – Air Drag – Terminal Velocity
Lecture 13: Potential Energy – Energy Considerations to Derive Simple Harmonic Motion
Lecture 14: Escape Velocities – Bound and Unbound Orbits – Circular Orbits – Various Forms of Energy – Power
Lecture 15: Momentum – Conservation of Momentum – Center of Mass
Lecture 16: Collisions – Elastic and Inelastic – Center of Mass Frame of Reference
Lecture 17: Impulse – Rockets
Lecture 18: Exam 2 review
Lecture 19: Rotating Rigid Bodies – Moment of Inertia – Parallel Axis and Perpendicular Axis Theorem – Rotational Kinetic Energy – Fly Wheels – Neutron Stars – Pulsars
Lecture 20: Angular Momentum – Torques – Conservation of Angular Momentum – SpinningNeutron Stars – Stellar Collapse
Lecture 21: Torques – Oscillating Bodies – Hoops
Lecture 22: Kepler’s Laws – Elliptical Orbits – Satellites – Change of Orbits – Ham Sandwich
Lecture 23: Doppler Effect – Binary Stars – Neutron Stars and Black Holes
Lecture 24: Rolling Motion – Gyroscopes – Very Non-intuitive
Lecture 25: Static Equilibrium – Stability – RopeWalker
Lecture 26: Elasticity – Young’s Modulus
Lecture 27: Fluid Mechanics – Pascal’s Principle – Hydrostatics – Atmospheric Pressure – Over Pressure in Lungs and Tires
Lecture 28: Hydrostatics – Archimedes’ Principle – FluidDynamics – What Makes Your Boat Float? – Bernoulli’s Equation
Lecture 29: Exam 3 review
Lecture 30: Simple Harmonic Oscillations – Energy Considerations – Torsional Pendulum
Lecture 31: Forced Oscillations – Normal Modes – Resonance – Natural Frequencies -Musical Instruments
Lecture 32: Heat – Thermal Expansion
Lecture 33: Kinetic Gas Theory – Ideal Gas Law – Isothermal Atmosphere – Phase Diagrams – Phase Transitions
Lecture 34: The Wonderful Quantum World – Breakdown of Classical Mechanics
Lecture 35: Farewell Special – High-energy Astrophysics



From the Big Bang to Dark Energy

A new entry, a different style (a comment to myself, again). Some time ago I’d be including a YouTube video, a more detailed explanation, etc. Not now (I’ll try not to be repetitive with such comments, 🙂

From the Big Bang to Dark Energy is the name I’m following through Coursera, one of the best MOOC platforms nowadays. Quite interesting, a bit short (4 weeks of duration), currently in week number 3. This has awakened the darkphysicist from his sleep. Thanks to physicists like Hitoshi Murayama (and his TA Brian) for being there and dedicate their time to teaching Physics for free.

Sinopsis of this really interesting course (extracted from Coursera):

About the Course

We have learned a lot recently about how the Universe evolved in 13.7 billion years since the Big Bang.  More than 80% of matter in the Universe is mysterious Dark Matter, which made stars and galaxies to form.  The newly discovered Higgs-boson became frozen into the Universe a trillionth of a second after the Big Bang and brought order to the Universe.  Yet we still do not know how ordinary matter (atoms) survived against total annihilation by Anti-Matter.  The expansion of the Universe started acceleration about 7 billion years ago and the Universe is being ripped apart.  The culprit is Dark Energy, a mysterious energy multiplying in vacuum.  I will present evidence behind these startling discoveries and discuss what we may learn in the near future.

Course Syllabus

Week 1: From Daily Life to the Big Bang
Week 2: Birth of Elements and Higgs Boson
Week 3: Dark Matter and Anti-Matter
Week 4: Inflation and Dark Energy