What Have I Been up to?

People often wonder about what I do.  Physics professors such as me are eternally busy, often doing self-imposed work at all hours of the day, including weekends.  One of the advantages of a faculty position is the flexibility to take some little bits of time off here and there to recharge ones batteries.

When I pay myself summary salary from a grant, usually for no more than two months out of the three summer months, I end up working all of the time.  Summer provides the opportunity to catch up on research backlog, which builds up during the academic year due to teaching and service commitments.

A week ago, I took Monday off to drive up to our wilderness north of Spokane to work on installing a solar power collection system.  Even though I had worked through the weekend, it was difficult to pull myself away from all the accumulated commitments;  I had considered cancelling the trip several time until I got behind the wheel of my car.

The outing was worth it.  Working in the wilderness under blue skies and pure air rejuvenates the body and mind.  It's the only activity that completely removes even the slightest pang of anxiety from the pile-up of work demanding my attention.  Upon my return, I am more efficient and approach the tasks at hand with a reduced level of anxiety.

A glimpse of my recent activities can be gleaned for a narrative I was required to provide with my annual review materials.  It is reproduced below in its raw and unedited form.  Please excuse all of the typos and awkwardness, which is partially due to my distaste for having to write about my activities -- a process akin to holding one's breadth while trying to quickly empty the trash at the county landfill.

Here it is:

As described below, much of my work integrates teaching and research, making a fuzzy demarcation between the two, such as turning our research-grade apparatus into one that can be built by a high school student.

Research

Since the last review, I published 10 papers in six distinct refereed journals, all of them in the top tier of their specialty.  The work spans from fundamental quantum mechanics to applications and covers cutting-edge research, pedagogy, and broad-interest topics.  Highlights of the work follows.

The highest impact paper was a massive 170-page invited review article/tutorial that appeared in Advances in Optics and Photonics and covers the new emerging field of photomechanics.  A related invited paper, which included new research results, appeared in Journal of the Optical Society of America B.  Most recently we published a definitive paper on the mechanisms of the photomechanical effect in dye-doped polymer optical fibers, which appeared in Applied Sciences.  The latter work combines several experiments and varying conditions and two independent theories that together pin down the mechanisms with more confidence than would be possible with a single measurement and theory.  These three papers together position our group at WSU as a leader in the field.

On the pedagogy front, we published several articles in the American Journal of Physics.  One paper describes using a mobile phone for collecting data at home, enabling isolated students to do labs remotely.  A more fundamental paper elucidates subtle concepts underlying the Quantum no-cloning theorem and entanglement.  Finally, the paper on quantum length introduces new ideas and paradoxes that challenge our understanding of quantum mechanics and measurement.

A fundamental paper that describes a new method of using a proxy state to account for the quantum continuum appeared in Optics Letters while an applied paper on distributed Bragg fiber lasers that self-heal after burning out appeared in Applied Physics Letters, earning an Editors Choice recognition.  A  unique paper on how the nonlinear-optical response of novel hybrid quantum systems can be controlled with topology appeared in Journal of the Optical Society of America B.

Our visibility in the field of photomechanical materials and devices continues to increase with increased international exposure.  I gave the Keynote Address on the topic at the SPIE meeting in San Diego and presented an invited seminar at the Abu Dhabi Campus of New York University in the United Arab Emirates.  I have also been invited to speak at an international meeting in Cetraro, Italy on this topic.

I have been invited to guest-edit a special issue on photomechanical materials and applications for Applied Sciences and have already assembled an international team of co-editors.  This will enhance our visibility in the field. 

The quantum work continues to generate interest.  I presented our work on quantum NLO theory at the Foundations of nonlinear Optics as an invited speaker held at the Air Force Institute of Technology in Dayton, OH.

My work in fundamental quantum mechanics and pedagogy was presented in two Colloquiums: one at Colgate University and one at Skidmore College.  In addition to the technical presentation, I also presented an overview of our department and graduate program for recruitment purposes.

Our work over the past 10 years has focused on the physics of photomechanical materials and their applications, understanding the mechanism behind self-healing in dye-doped polymeric materials, and studying the quantum origins of the nonlinear-optic response.  We are in the process of transitioning into new areas while fortifying existing research strengths.

Taking advantage of the NLO Lab’s present strength in photomechanics, we are pursuing single-PI grants to support work with collaborators who make materials.  The near-term goal is to reinforce our interactions with international colleagues such as the exceptional groups at Tempere University in Finland and others in Morocco and Japan.  The long-term goal is to compete for larger grants.  The self-healing work, on the other hand, is attractive based on our past dominance in the field.  We have submitted a white paper to AFOSR, who share an interest in the topic.  However, we have experienced delays due to personnel changes at AFOSR.  Our group is still competitive in quantum nonlinear optics, so I plan on sending a proposal to NSF.  My efforts in the near future will focus on getting at least one of these three viable projects funded.

To leverage our unique abilities in quantum NLO, I am investing a significant effort in developing a framework for implementing quantum computing using nonlinear optics to color-entangle photons.  Given the large investment being made by the United States in quantum computing due to its importance to national security and competitiveness in the high-tech markets, the rewards are high but so are the risks.  I plan to focus most of my energy on this work throughout this calendar year and working on white papers with our larger physics-based team.

Teaching

I continue to teach undergraduate and graduate courses, advise graduate students in their masters and dissertation research, and advise undergraduates who are working on research and thesis projects.  Since 2018, I have graduated three PhD students and have served on numerous graduate thesis and dissertation committees.   Many of these students have been awarded mini-grants from within the university at the departmental and college level.  Traditional courses that I have taught over this period include Physics 320, Physics 533, Physics 534 and Physics 545.  I arranged for free licenses of Origin to be made available to students in Physics 320 and Physics 545 for class projects.  The first author in the American Journal of Physics publication on using cell phones for data was an undergraduate student whose research originated as a class project.  I also did similar projects with students taking the undergraduate seminar.

Service

I am active in service at all levels within the university and in my profession.  I advise the student chapters of OPTICA/SPIE, which do lots of outreach and run the laser maze during various university events.  I’m on the departmental committee for producing the APS video which will be used for recruitment, work with the College on undergraduate weekend recruitment presentations and have been involved in producing the departmental Comprehensive exam.

At the professional level I am on the editorial board or editor for several journals, act as a reviewer for more journals than I can count and have been awarded IOP trusted reviewer status.  The citation reads: “IOP trusted reviewer status acknowledges that you have demonstrated a high level of peer review competence, with the ability to critique scientific literature to an excellent standard.  You are one of our first reviewers to have achieved this status, so congratulations!”  I am active in organizing international conferences, two of which I founded: International Conference on Organic Nonlinear Optics (ICONO) and Foundations of Nonlinear Optics (FoNLO). 

Extreme Physics

In our culture, the word "extreme" has taken on a new meaning because of its use in naming new sports that are dangerous. By "extreme physics," I mean the physics of a phenomena when one of its defining parameters is at an extrema; that is, a minimum, maximum, or point of inflection. Mathematically, an extrema of a function is defined as the point were the first derivative is zero. In many ways, extreme physics can be just as exciting as extreme sports.

It interesting to me that the underpinnings of physics are based on extremes. Surely I am not unique in thinking this way; but, I am excited by the topic because one of my projects is based on the theme of using the limits of the nonlinear-optical response to discover new things about light-matter interactions that in the end may lead to a deeper understanding.

As we have been digging deeper and deeper, new patterns are emerging. This regularity, however, is only observed at the extremes of the nonlinear-optical response. Given how all of known physics manifests itself by an extrema, it is pretty exciting to think that we may be on the verge of discovering truly new physics.

There are other projects that are going well and have potentially very exciting ramifications. For example, we are in the process of fine-tuning a new model of the self-healing process. But this is not just a model in the form of an equation that we use to fit our our data (which we are indeed doing), but the parameters represent new phenomena. If the model fits, we are potentially looking at new theory that may be generally applicable to many things. The more general the applicability of our work, the happier my mood.

I end here by lifting an excerpt from a review article we are writing for Physics Reports. It is a more detailed description of what I have written above.

The extremes of physics are characterized by unique behavior. For example, the second law of thermodynamics states that entropy cannot decrease in a closed system. The special case when entropy change is minimized (i.e. it remains unchanged) defines reversible thermodynamic processes. The maximum efficiency of a heat engine requires a reversible process. Calculations of reversible heat engine efficiencies led to the definition of entropy. While motivated by practical applications, entropy has become one of the most important fundamental concepts in physics.

Quantum mechanics is based on the fact that certain quantities cannot be simultaneously measured to arbitrary precision. To accommodate this observation, variables such as momentum and position are generalized to become operators that do not commute. The mathematical formalism naturally leads to the uncertainty principle, which states that there is a lower bound to the product of the position and momentum uncertainties. The fact that uncertainties are constrained by a lower bound is the basis of quantum mechanics, which describes a vast richness of new phenomena that is inexplicable using classical mechanics.

The principal of energy conservation originates from the more general concept of a Hamiltonian, which yields the equations of motion through a process of finding the extrema of the action. These ideas carry over into the quantum realm in the formulation of path integrals, which bring out the wave nature of matter. The absolute maximum speed limit defined by the speed of light, on the other, leads to non-absolute time, where observers in different coordinate systems view the same phenomena but from the perspective of a rotation in four-dimensional space-time. The marriage of relativity with quantum mechanics as embodied by the Dirac equation led to a natural way of accounting for the electron spin, and as a bonus unexpectedly predicted the existence of antimatter.

Clearly, the extremes are fertile soil from which the most fundamental concepts in physics grow. As we later show, the fact there there is a fundamental limit to the nonlinear-optical response of a quantum system defines an extreme that is characterized by several features. For example, while many states of a quantum system contribute to the nonlinear-optical response, at the upper bound only three states are found to contribute. This was originally postulated as a hypothesis and later confirmed to be true for many quantum systems, though it has not yet been rigorously proven. As such, it is referred to as the three-level ansatz.

We will show that systems with a nonlinear response near the fundamental limit share other properties. Why this is true is not yet understood; but, the fact that certain universal properties appear to be associated with the extremes of the nonlinear response hints at fundamental causes, perhaps grounded in new physics, which become apparent only under scaling rules that follow naturally from these limits.