Relaxation

This is what your heart does when it pushes blood around your body, what some electrical circuits do as they charge and discharge and cell division too, likely does that. What I am talking about is “relaxation oscilations”.

Remember the normal heartbeat patterns where you see a spike followed by very little activity and then a spike again? That is an example of relaxation oscillations. A number of chemical, mechanical and hybrid systems are known to exhibit such oscillations. They crop up in control problems too as we shall see.

In many systems that are controlled, the basic mechanism is this. If the system is going to stop, the control puts energy into it, to keep it going. On the other hand, if the system is taking too much energy, the control reduces it.

Think about it in terms of the hert. If it tries to stop, the body is designed to keep it going and if its potential is going too high the body is designed to bring it back to normal too. So what we get is known as the phenomena of nonlinear damping. In such oscillations, for small value of oscillations variable, the damping is large and negative. For large variable value the damping is large and positive to reduce the oscillations. This finally gives the blip like oscillations that we see in the heart. A textbook example for an interested student is the Van der Pol system.

Essentially nonlinearity rocks.

Quantum Ghosts

In quantum mechanics there are several effects which are spooky and yet the theory relates very well with observations.

1. Schrodinger’s cat: Alive and dead at the same time (ok a bit of (or quite a lot of) a stretch as this is seen only at atomic scales).

2. Being present at two places at once: An atom can be present at two places at the same time. This was shown in an elliptical arrangement of Cadmium atoms. An atom inside could be sensed at both the foci.

3. Same as above, a particle seems to go through both the slits at the same time in the double slit experiment.

4. Ghost orbits: classical orbits which don’t exist at a given parameter appear to change probability distribution in a quantum state.

All these effect are real, Have theories which help make predictions in various scenarios. However the interpretation of the quantum theory, known as the Copenhagen interpretation can not be intuitively understood, the major argument in favor of the theory being that it works.

“Quantum supremacy, the first 200 seconds for Google, a giant leap for mankind?”

Learning

One of the best way to learn is by experimenting and one very convenient place for experimentation is the kitchen. With a lot of information available on the internet it is now even more fun place to be. Following are some of my insights from various experiments.

1. To make Dosai unless you are an expert, use a non stick pan and after each Dosai is done cool the pan with a sprinkle of water. The batter spreads better on a cooler pan.

2. Idlis come out better if the batter is thick and not too smooth.

3. Noodles (not maggi but the plain ones) can be a fast food that is nutritious. Stir fried crispy veggies and some readymade spices make a big difference.

4. While making vada, take the daugh on a wet palm, smoothen the top with wet fingers, make a hole and gently slide into the frying pan. I had never known how easy it becomes with using water appropriately.

5. To make Tehari, soak rice for 2 to 3 hours and strain. Frying this rice with seasoning and veggies until the rice starts sticking. Add hot water and fast cook to have a delicious treat.

6. For stuffed paratha, it helps is the daugh has a little less water than the roti dough and the stuffing is cool.

Happy navratri and hope you enjoy some hot snacks this wet monsoon.