Evan J. Arena, Ph.D.

About Me

I am a lecturer and lab coordinator of physics at Bryn Mawr College. I am a cosmologist, which means that I am an astrophysicist who is interested in the "biggest" questions about the universe. I obtained my Ph.D. in physics at Drexel University in 2024, where my research focused on mostly theoretical cosmology. Before that, I received my B.S. from Stony Brook University in 2017 where I double-majored in physics and astronomy/planetary sciences. I am originally from Long Island, New York.

Teaching

I am a lecturer of physics at Bryn Mawr College.

For a list of physics courses at Bryn Mawr College, click here.

In Fall 2025, I am teaching:

• PHYS B101-001: Introductory Physics I (for postbacs)

  Course description: This is the first of two courses in the introductory physics sequence intended primarily for students on the pre-health professions track. Emphasis is on developing an understanding of how we study the universe, the ideas that have arisen from that study, and on problem solving. Topics are taken from among Newtonian kinematics and dynamics, relativity, gravitation, and fluid mechanics. An effective and usable understanding of algebra and trigonometry is assumed.

In Spring 2026, I am teaching:

• PHYS B122: Classical Mechanics

  Course description: This course covers Newtonian Mechanics of single particles, systems of particles, rigid bodies, and continuous media with applications, one-dimensional systems including forced oscillators, scattering and orbit problems.

• PHYS B125: Physics of the Cosmos: A Journey through Our Universe

  Course description: What can we discover about the Universe, and our place in it, from observations of the night sky? What is the James Webb Space Telescope looking for? What is dark matter and dark energy? Are we alone in the Universe? This course is a survey of topics in astronomy, astrophysics, and cosmology. We embark on a cosmic journey through space and time, where we examine our solar system, our galaxy, the Universe, and the concepts in physics that allow us to describe the cosmos.

  I am particularly excited to teach this course. This course is intended for non-physics majors who are interested in learning about our place in the Universe.

Courses I have previously taught at Bryn Mawr:

• PHYS B101-002: Introductory Physics I for undergraduates (Fall 2024)
• PHYS B102-002: Introductory Physics I for undergraduates (Spring 2025)

My Teaching Before Bryn Mawr:

At Drexel University, I was a teaching assistant for five years. I was a recitation instructor for the courses PHYS 100: Preparation for Engineering Studies, PHYS 152: Introductory Physics I, and PHYS 154: Introductory Physics III (I also served as a lab instructor for PHYS 154). I was a grader for PHYS 131: Survey of the Universe and PHYS 231: Introductory Astrophysics, as well as a guest lecturer for PHYS 231. In 2020, I was honored by the graduate college with a "Teaching Assistant Excellence Award." Then, in 2021, I was awarded a "Continuing Excellence in Teaching Assistance Award." I was given the "Continuing Excellence in Teaching Assistance Award" again in 2022 and again in 2023!

At Stony Brook University, I was a lecturer for the Della Pietra High School Applied Math Program in Spring 2017. My lectures included calculus as well as Newtonian mechanics, special relativity, and cosmology as applications of mathematics.

Research

When I was born in the 1990s, the field of cosmology was making some of the most paradigm-shifting discoveries in all of physics. Since then, rapid progress has been made in this once overshadowed and speculative field. Indeed, it seems as though more advancement has been made in the last twenty years than the last century. Owing to the work of cosmologists across the world, there now exist experimentally verified predictions about the Big Bang, as well as promising ways forward for understanding dark energy, dark matter, cosmic neutrinos, and the early universe. It is said that we are currently living in the "golden age" of cosmology -- and I suspect that this may be true.

My research in theoretical physics focuses on several aspects of cosmology. I am particularly interested in how perturbations in the very early universe (right after the Big Bang) have lead to the large-scale structure made of baryonic and dark matter we see today, the gravitation responsible for growing the seeds of these primordial fluctuations, and how dark energy has lead to an accelerated expansion of the universe.

The goal of my research is to build tools that help us extract information from cosmological surveys. During my Ph.D., I developed a tool that measures flexion, a second-order gravitational lensing effect. Traditionally, weak lensing makes use of shear, by looking for coherent alignment of galaxies in a field. Unlike shear, flexion directly probes variations of the potential field. As such, flexion is relevant on smaller scales than shear. This allows us to collect additional information from surveys that might otherwise be thrown away. To this end, I created a full theoretical formalism for ``cosmic flexion'' -- a family of cosmological weak lensing signals originating from the large-scale structure of the universe. I discovered previously unknown cosmological weak lensing signals and posited the existence of non-commutativity in weak lensing. I am also currently working on making the first ever measurements of cosmic flexion.

I am also interested in modified gravity -- the landscape of theories of gravity that include general relativity and its variants. Specifically, I am interested in how cosmological measurements can help us answer the question of whether general relativity is the correct theory of gravity.

In the past, I was a member of the DOE Cosmic Visions Dark Energy 21 cm Working Group. This group focuses on intensity mapping with the neutral hydrogen 21 cm emission line as a cosmological probe. I had also been involved with the Baryon Mapping eXperiment (BMX) at Brookhaven National Laboratory.

Contact

email: earena@brynmawr.edu

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