How do you introduce yourself, scientifically?

My name is David Kolchmeyer and I am a theoretical physicist. I’m interested in quantum gravity, which is a theory of gravity that obeys the rules of quantum mechanics. Quantum mechanics is the fundamental framework upon which much of my field is built. I’m most interested in the properties of black holes, which are a good system for studying quantum gravity.

What are the implications or broader impacts of your work? What kinds of questions are you trying to answer?

There are no near-term technological applications of my work, so the impact is expanding our knowledge of the universe. 

One of the things I want to understand is how black holes store and process information. If you throw matter into a black hole, what happens to the information that is encoded in that matter? One way to think about this question is ‘What happens to a person who goes into a black hole? What would their experience be?’. 

That might seem like a simple question, but people have reached contradictions in trying to understand it. Stephen Hawking’s original proposal was that information is destroyed. If true, that would be a radical departure from everything else we know in quantum mechanics – there is a concept called unitarity, the idea that information cannot be destroyed.

Quantum mechanics predicts that black holes emit radiation. Eventually, they will emit all their energy away, and there will be no black hole left. If you had sufficiently powerful instruments and could collect and analyze all of the radiation that came from the black hole, would you be able to figure out what information entered the black hole during its formation? Or, is that information destroyed? Black holes do exist in nature, but it is extremely difficult to measure their radiation, so we rely on theoretical models in order to understand them.

What do your data look like?

Many scientists start with a natural phenomenon, and they assume that it is governed by a theory, and then they do experiments and collect data to probe that theory. In my work, I usually start with a particular theory and then explore its implications. The ‘data’ that we use are the conclusions about the behavior of a black hole, for example, that we can deduce from the definitions of the theory.

If the theory is complete, you can do your calculations and tell an interesting story. But sometimes the theory might be incomplete. This is where artistry might be required; you have to be creative and construct a new theory. We write down equations and create mathematical models to formalize our ideas about how black holes behave. 

Once you develop this model, this set of equations, what do you hope it reveals?  How do you use equations to come to conclusions? 

Equations are the language we have for communicating ideas or intuitions about how a system works. There are two sides to every story: there are the words, the intuition, and there are the equations, the math. I personally don’t think in equations. I think of an intuitive picture for how a system works. Then, in order to convince others that my idea is correct I have to capture it using an equation; I present the equation, showing what every term represents, and relate it to an intuitive understanding of a black hole, for example. 

How do you verify that your models/equations are valid?

A model has to be self-consistent, and it has to tell a plausible physical story that agrees with prior discoveries. 

Can you explain some of the steps that go into generating these models? What does a typical day look like for you?

Some days I’m engaged in meetings with collaborators and my advisor, and some days I’m working alone. A typical day involves reading papers and thinking about discussions I’ve had in meetings. These discussions are really important for establishing our goals and next steps. The work itself is writing down and solving equations that tell us the consequences of our models and intuitions. A lot of that is done with paper and pencil, with the aid of computer programs. You need to figure out what equations you should try to solve; they can be quite complicated, so you want to have confidence that the equation you are trying to solve is meaningful. 

What makes a theoretical physicist different from other scientists?

One thing that sets us apart is that, while we are happy to study the actual universe that we live in, we also enjoy studying other universes. These other universes have different laws of nature, and they may have different numbers of spatial dimensions. Most other scientists aren’t as concerned with other kinds of universes. But there is a mathematical basis for studying other universes, and the details of those different universes are essential to understanding more basic principles of physics. When modeling other kinds of universes, it is not true that anything goes, which is why we think that what we are doing is still relevant. 

Is there a common misconception about your field? 

There is a misconception that we can simply make things up. It’s significant that predictions made by theoretical physicists have eventually been confirmed. For example, it took 100 years for Einstein’s gravitational waves to be observed in nature. Within theoretical physics, there are some subfields that are more concerned with the outcome of experiments, and other more ‘formal’ subfields (including mine), where we set aside experiments and think at a more abstract level.

Is there anything you would tell people interested in becoming a theoretical physicist?

It’s extremely exciting! Theoretical physics is full of surprises. You might think that a problem is really hard to solve, but then one day you get a moment of clarity and you can write up your results. It is truly a field of exploration. And it’s exciting that somehow the exploration can all take place in your mind, but at the same time the work has implications for our understanding of the real world. It’s amazing how much you can explore and understand just by taking an established set of interesting and deep principles and pursuing them ruthlessly until their logical conclusions. It’s also cost-efficient research – all I need is a good box of pencils.

To learn more about David’s work:

This interview with David Kolchmeyer was conducted and edited for space and clarity by Malinda J. McPherson in October 2020. 

Malinda J. McPherson is a PhD candidate in the Harvard University/MIT Program in Speech and Hearing Bioscience and Technology.

Cover image by WikiImages from Pixabay.

This piece is part of our special edition on the day-to-day lives of researchers working in many different fields of science. Are you interested in learning about a different type of scientist? Check out the rest of the special edition!

2 thoughts on “What Does A Theoretical Physicist Do?

  1. E=VPT/t (T=Universal time t=clock time) at black hole t=0 but T&E still increase, everyone was blinded by the measurement problem.

    Using this equation where the total energy is defined by the Volume V, momentum P and universal time T, we measure using specific intervals of clock time units t (seconds, hours, nanosecond etc) Because at the event horizon of a black hole the time recorded is zero but universal time always increases relative to the “beginning” then the fact that T always increases means Energy always increases. The reason physicists have concluded that energy is conserved is due to the limitations of the measurement problem. We can only ever measure in one dimension of time and space in any discrete act of measurement. Noether’s Theorem is limited to one dimension in any discrete act of measurement. In the double slit experiment the range of where that dimension in space will be located is reduced to the space between the particle gun, the slits and the back screen. It isnt that the wave function collapses, the range of detecting the wave is reduced. All main principles are summarised into small bite sized videos on my youtube channel.
    This one explains the most fundamental foundation of living physics that modern physicists have no explanation for… energy. Quantised energy.

    This equation came as the result of an inequality that beats the measurement problem to crack the double slit experiment. As the interference pattern on the back screen hinted, energy propagates out in waves in every direction. The measurement problem is that we can only measure between 2 points in space and time in any discrete act of measurement. We usually compile all those individual measurements together when doing complex calculations. In the double slit experiment the wave function doesnt collapse upon more focused measurement, the very act of narrowing the focus also narrows the possible range of hits on the back screen which must arrive within the reduced range of focus. Like the delayed choice quantum eraser experiment the possible outcomes have been predetermined by the parameters of the experiment setup. The fact is that when we setup the experiment to detect for which way the “particle” makes it through one or other slits every time which only a wave would do. If it were particles being fired most would hit the front screen and few pass through the slits. The particle nature is in fact the field particles which exist in every intersection in the spacetime fabric/dark matter lattice/cosmic web and the wave is what we detect passing through one dimension/line of field particles giving the optical illusion that it is a travelling particle.

    Another study from Indian astrophysics this year shows the redshift of distant galaxiesincreases in phases, further supporting my assertion that redshift is primarily due to the increase in gravity sapping energy en-route not primarily due to doppler effect. The fact that the light passes through gravitational zones which rotate causes more or less energy to be sapped in phases relative to how far or near large massive objects are to the direct path of light.

    Full ToE that solves and unifies everything is available open access free to anyone in the world regardless of income.

    There is a reason everyone should take this really seriously, the current model of star formation which tends to ignore the many anomalies like the neutral H anomaly is incorrect, they may seem like minor problems but hairline cracks in a perfectly fine looking bucket renders it useless when it is put to the test. The new maths of energy creation shows Einsteins Relativity is further validated/confirmed, our sun is a white hole that generates it’s own energy and matter. The evidence shows it goes nova every 12,000 years usually causing mass extinctions, the last one was 12,000 years ago which seems to have been what wiped out the Neanderthals, woolly mammoths and sabre tooth tigers then the reduction in the suns energy after the expulsion of built up energy led to the ice age. There are two types of nova (at least) one where the matter explodes as in a supernova and one where energy is squeezed out over a short period of time (similar in a sense to the corresponding quantum level photon emission in atoms when energy is built up and forces the photon energy out and into a higher energy state). The evidence I have come across is that the next one is due anytime between now and 2050, links to the evidence is provided in the first section in my paper. If we are not prepared in some way and it takes the world by surprise it will be like getting hit by a bomb and anyone who survives will likely face a real zombie apocalypse scenario with satellites, power grids and therefore supply chains put out of action with the electrical storm that will follow roughly 18 hours after any initial flash, plus the wave of matter, much of it radioactive, that will follow after the electron storm. Please take it very seriously and challenge everything you have falsely concluded due to the measurement problem. We cant stop it but we can try our best to prepare and we don’t really have any time to waste. 

    I am having immense problems trying to connect with super busy physicists blindsided by the measurement problem and came across your email online as someone who may be able to understand and raise the discussion/alert among those higher up in positions of influence. I tried to add a bit of humour into my work but I’m not sure it didn’t backfire and people think I am the joke. Expect resistance, I have found it is very difficult for many to listen to what overturns a very long held model that seems to be almost watertight in some minds. I hope and pray you have better success than I have been able to have so far.



    PS there are multiple issues with peer review in a divided world where information is power, where people schooled in the incorrect “facts” concluded under the limitations of the measurement problem may find it hard to efficiently grasp the true model and where people without money (like me) are effectively blocked from participating.

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