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Structure of REU Program�“Research in Symmetries�at the University of Kentucky”

Christopher Crawford

Director of REU Program

(859) 421-9612

c.crawford@uky.edu

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REU Program Contact Information

Renee Fatemi -> Ganpathy Murthy Department Chair

renee.fatemi@uky.edu 859-257-2664

murthy@g.uky.edu 859-257-4729

Nina Raynolds Department Manager

Nina.Reynolds@uky.edu 859-257-6101

Christopher Crawford Director of REU

c.crawford@uky.edu 859-421-9612

Jennifer Wilhelm Co-PI for Assessment

jennifer.wilhelm@uky.edu 806-543-5488

Max Brown REU Coordinator - Orientation

Maxwell Ankrah REU Coordinator - Classes

Mainak Das GA – Research Support

Mickey Demos GA – Research Support

Ambuj Jain GA – Research Support

Komal Komal GA – Research Support

Raihana Toma GA – Research Support

Heather McCall GA – Assessment

Cameron Richards GA – Assessment

https://pa.as.uky.edu/reu 859-257-6722 (office)

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Physics and Astronomy REU program in Kentucky!�

Currently in 6^th year of program

This REU program was funded by the NSF to combat a very different asymmetry in opportunity in Rural Kentucky / Central Appalachia, and in the following infographic, you can see the previous gap of REU sites in this region. Thus, many of you come from all corners of Kentucky. We hope that you will become ambassadors for Science and Technology in your communities and advertise the REU by word of mouth in your home institutions. We welcome those of you not from Kentucky, and hope you enjoy all the richness the state (and UK) has to offer.

Although NSF only funded for 6 spots for participants this year, we have been able to expand the reach of the program through a variety of funding mechanisms and situations. Note that the distinction of NSF funded vs other sources is only relevant in terms of reporting to NSF. All of you who fully participate in the REU program should include this experience in your resume and applications to graduate school. Some of you have arrangements to participate remotely and so all classes and workshops will be offered remotely through this Zoom link.

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Goals of the REU program

Immersive research experience

Discover your own strengths
Refine career goals
Learn research techniques
Independent inquiry
Research vs Coursework education

Form identity as Physicist/Astronomer

Develop professional network�build friendships across the nation
Take steps along “Research Ladder”
Strengthen application to Graduate School

This REU program was funded by the NSF to combat a very different asymmetry in opportunity in Rural Kentucky / Central Appalachia, and in the following infographic, you can see the previous gap of REU sites in this region. Thus, many of you come from all corners of Kentucky. We hope that you will become ambassadors for Science and Technology in your communities and advertise the REU by word of mouth in your home institutions. We welcome those of you not from Kentucky, and hope you enjoy all the richness the state (and UK) has to offer.

Although NSF only funded for 6 spots for participants this year, we have been able to expand the reach of the program through a variety of funding mechanisms and situations. Note that the distinction of NSF funded vs other sources is only relevant in terms of reporting to NSF. All of you who fully participate in the REU program should include this experience in your resume and applications to graduate school. Some of you have arrangements to participate remotely and so all classes and workshops will be offered remotely through this Zoom link.

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Symmetries

Continuous Symmetries

space-time translation
rotational invariance
Lorentz boosts
gauge invariance

Noether’s Theorem� continuous symmetries� correspond to� conserved quantities

energy-momentum
angular momentum
center-of-momentum
electric charge

Discrete Symmetries

parity P : x → -x
time T : t → -t
charge C : q → -q
particle exchange� P₁₂: x₁ → x₂

Discrete Theorems

spin-statistics theorem
CPT theorem

SPS Cosmic Lunch

5

position �symmetry

conserved �momentum

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Discrete Symmetries

SPS Cosmic Lunch

6

CPT theorem: ALL laws are invariant under CPT

L

R

CP (charge, parity)

100

km/h

100

km/h

99.7

km/h

T (time)

I’m coming

home …

Be careful, some idiot’s

going the wrong way

on the freeway.

Only one? They’re

all over the place!

A little more seriously, let me talk about some discrete symmetries like parity in the context of cars.

Imagine two countries separated by water where cars drive on the opposite sides of the road.

So in one country we have left-sided cars, and in the other, right-sided cars.

Now if I drive through this tunnel, I change from a right-handed car to a left-handed car.

As a conscious law-abiding citizen, I ask myself: are the laws the same now?

For the strong force, electromagnetism, and gravity, I get the reassuring answer: yes.

But for the weak force, I get a complete shock: Right-handed cars are absolutely illegal.

The same goes for left-handed anti-cars.

We see that charge conjugation, going from a car to an anti-car in the same lane is also forbidden,

because then we could convert back to a right-handed car.

So neither charge conjugation nor parity have a symmetry are preserved by the law.

In the car world this makes sense and saves a lot of headaches

(and neck pain), but in the particle world, it makes us ask

uncomfortable questions, like why like this country and not that?

Is some other symmetry preserved? Maybe: I can go from a left-handed car to a right-handed anti-car.

It turns out that this symmetry is very closely respected, but not exactly.

Is all lost? There is one other symmetry: Time, which is represented as driving backwards.

But now you say: isn’t an anti-car just a negative energy car driving backwards in time? Why yes!

As far as I can tell, that is the jest of the CPT theorem, which is closely related to the Pauli exclusion principle.

With all these deep and natural symmetries, it’s no wonder that this poor driver was overcome with charge-confusion.

Now a disclaimer: Physics students, do not use this model to answer questions on your tests.

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Crystal Symmetry

SPS Cosmic Lunch

7