What do theoretical physicists do?

[George Keeling]

I took great comfort reading a New Scientist article on the Perimeter Institute, Canada where top theoretical physicists pass the day. They asked four how they get through the day. Two replies gave me great comfort:

Asimina Arvanitaki
I spend most of my time being confused about things and feeling like an idiot...

Avery Broderick
I spend most of my days feeling very stupid. I’ll get in front of the blackboard, Eye of the Tiger playing in my head, write something, erase it, change my pose, write something else, erase it, ad infinitum...

That's exactly how I feel most of the time!

The article is here. Sadly you need a subscription to see all of it.

 

[ZapperZ]

I took great comfort reading a New Scientist article on the Perimeter Institute, Canada where top theoretical physicists pass the day. They asked four how they get through the day. Two replies gave me great comfort:

Asimina Arvanitaki
I spend most of my time being confused about things and feeling like an idiot...

Avery Broderick
I spend most of my days feeling very stupid. I’ll get in front of the blackboard, Eye of the Tiger playing in my head, write something, erase it, change my pose, write something else, erase it, ad infinitum...

That's exactly how I feel most of the time!

The article is here. Sadly you need a subscription to see all of it.

But those statements mainly describe what they FEEL, not what they DO.

It is also why I chose to be an experimentalist.

Zz.

 

[George Keeling]

I chose to be an experimentalist

It's great to know that experimentalists NEVER doubt their own ability

 

[ZapperZ]

It's great to know that experimentalists doubt their own ability

How did you come to that conclusion based on what I wrote? You misinterpreted what I meant.

Zz.

 

[George Keeling]

You misinterpreted what I meant.

Oops I missed out a vital word! Does that make more sense?

 

[Vanadium 50]

Does that make more sense?

Yes, but it doesn't seem like a very nice thing to say. Maybe you should make a third try.

 

[ZapperZ]

Oops I missed out a vital word! Does that make more sense?

That isn't what I meant either! Experimentalists often have the ability to check with Mother Nature if what they think about is valid. We don't have endless conversation with a "blackboard".

Zz.

 

[George Keeling]

Zz.

Sorry. I took the signature Zz to mean that the writer was bored and dismissive of theoretical physicists to the extent that he/she was falling asleep. I now realize, it was just short for ZapperZ.

 

[Dr. Courtney]

Having published plenty of papers in both theory and experiment, here is my take:

The main task of the theoretical physicist is to predict the outcome of future experiments, usually in a way that has not been done before. Yes, there are lots of dead ends and blind alleys. Lots of time is spent going down unproductive paths, and important qualities of the theoretical physicist are determining a priori which paths are more likely to be productive, and seeing how to stop going down unproductive paths sooner rather than later. Knowing how far to back up and re-start is also essential.

In my days doing theoretical atomic physics, most of my time was spent on computations - writing and running atomic physics codes. Less time was spent deciding what to look for and which paths to take, but that time and those decisions were ultimately more important.

In my days doing theoretical blast physics, less time was spent grinding out computer computations, and more time was spent in gedenken experiments about the competing hypothetical injury mechanisms about what experimental evidence supporting each might look like, searching the literature for available data, and brainstorming how to connect those dots.

The main task of the experimental physicist is to test the available theoretical predictions or (more rarely) to conduct interesting experiments in areas where there are no clearly articulated predictions.

In my days doing experimental atomic physics work, this meant performing laser spectroscopy experiments in systems that were classically chaotic and amenable to both semi-classical approximations and to rigorous quantum mechanical calculations. There were no surprises on the quantum mechanical side - just insight into which quantum techniques worked better (faster and less memory intensive calculations.) There were some surprises and valuable insights and confirmations on the semi-classical side. But just as for theory, the knack for deciding which experiments to do and backing out of blind alleys is essential. However, the blind alley of the experiment that is too hard to do is just as important to recognize as the experiment that is less interesting than anticipated even if done correctly.

In my days doing experimental blast physics work, I ended up having more of a knack for inventing cost-effective laboratory blast wave simulators - stuff more appropriate for Review of Scientific Instruments than for Phys Rev or journals reporting new scientific results. Theorists had been trying to use modeling approaches to optimize designs of shock tubes with less success. I just went out, bought the hardware, and iterated the designs until I had what was needed. It turned out my experimental approach was faster and cheaper (due to the difficulty with the simulations). We would have preferred to focus more on experiments testing the most important theoretical predictions, especially after we invented our first couple laboratory simulators. But we realized these experiments were beyond our capabilities, so we limited ourselves to testing less important theoretical predictions and inventing new devices. Our awareness of our limitations yielded fewer blind alleys.