Canada

The observed gender gap in physics testing is a problem which plagues physics education. Many studies in universities across North America show that female students consistently perform worse than male students on written examinations and concept inventories, though the size of this performance gap varies from study to study. In some cases, this gender gap in performance has been linked to more negative perceptions and lower confidence in physics among female students. The goal of our study was to determine if there is a gender gap in perceived confidence and interest in physics at the introductory level. 
An online survey was distributed to the three streams of introductory physics students at McMaster University which had students answer a range of questions about their undergraduate degree, background, comfort, confidence, and other metrics. We asked students to rate their interest and preparedness in physics before and after taking their introductory course. Upon analysis of these results, a clear gender gap was observed in key areas such as perceived confidence within the course, and the student&#39;s level of interest in physics. Female students consistently reported lower perceptions of preparedness and interest in the course relative to their male counterparts. However, when analyzing the change in interest and confidence, the gender gap greatly varied dependant on the introductory stream. An online survey will also be distributed to upper year physics students to probe whether the confidence and interest gap extends throughout undergraduate degrees, or whether the gap narrows as students get accustomed to the university environment. Lower confidence in first year could negatively impact the performance of female physics students at McMaster and could contribute to a lack of gender diversity in upper year physics programs.  
The affirmation of the student gender gap in confidence within introductory physics courses at a large Canadian institution is a troubling but crucial step in creating a welcoming and inclusive physics education environment for all students.

CAP Virtual Congress 2021

Investigating the Gender Gap in Introductory Physics Courses

introductory physics

physics education

gender

**WELCOME TO THE 2021 CAP VIRTUAL CONGRESS UNDERLINE PLATFORM**

The CAP staff and our organizing and program committees are pleased to welcome you to our 2021 Congress filled with plenary talks, technical sessions/talks, student presentations and competition sessions, workshops, and several symposia offered by the CAP divisions and its partners.  

You will also have opportunities to network with other delegates through the Gathertown platform accessed by selecting the lounge or posters button on the left.

Registered delegates should use the schedule button to call up the details of the session/event they wish to attend.  Each sessions includes a link to access the online platform where the event is taking place, either within Underline or through other Congress-related Zoom meetings.  

Invited speaker talks are identified with an (I), and student competitors include a (G*) or (U*) to identify graduate or undergraduate presenters.

Please take the time to check out the information about our sponsors and exhibitors, request further information, or leave a note of thanks for their support.

General information about the Congress can be found on the CAP website Congress pages at https://www.cap.ca/congress/2021.

Looking for a specific talk?   A full searchable list is available on our Indico Congress site at https://indico.cern.ch/event/985448/contributions/

We look forward to sharing this exciting week with you!


The observed gender gap in physics testing is a problem which plagues physics education. Many studies in universities across North America show that female students consistently perform worse than male students on written examinations and concept inventories, though the size of this performance gap varies from study to study. In some cases, this gender gap in performance has been linked to more negative perceptions and lower confidence in physics among female students. The goal of our study was to determine if there is a gender gap in perceived confidence and interest in physics at the introductory level. 
An online survey was distributed to the three streams of introductory physics students at McMaster University which had students answer a range of questions about their undergraduate degree, background, comfort, confidence, and other metrics. We asked students to rate their interest and preparedness in physics before and after taking their introductory course. Upon analysis of these results, a clear gender gap was observed in key areas such as perceived confidence within the course, and the student's level of interest in physics. Female students consistently reported lower perceptions of preparedness and interest in the course relative to their male counterparts. However, when analyzing the change in interest and confidence, the gender gap greatly varied dependant on the introductory stream. An online survey will also be distributed to upper year physics students to probe whether the confidence and interest gap extends throughout undergraduate degrees, or whether the gap narrows as students get accustomed to the university environment. Lower confidence in first year could negatively impact the performance of female physics students at McMaster and could contribute to a lack of gender diversity in upper year physics programs.  
The affirmation of the student gender gap in confidence within introductory physics courses at a large Canadian institution is a troubling but crucial step in creating a welcoming and inclusive physics education environment for all students.

poster

A relativistic theory of gravity like general relativity produces phenomena differing fundamentally from Newton’s theory. An example, analogous to electromagnetic induction, is gravitomagnetism, or the dragging of inertial frames by mass-energy currents. These effects have recently been confirmed by classical observations. Here we show, for the first time, that they can be observed by a quantum detector. We study the response function of Unruh De-Witt detectors placed in a slowly rotating shell. We show that the response function picks up the presence of rotation even though the spacetime inside the shell is flat and the detector is locally inertial. The detector can distinguish between the static situation when the shell is nonrotating and the stationary case when the shell rotates and the dragging of inertial frames, i.e., gravitomagnetic effects, arise. Moreover, it can do so when the detector is switched on for a finite time interval within which a light signal cannot travel to the shell and back to convey the presence of rotation.

Quantum Detection of Inertial Frame Dragging

We derive Loop Quantum Gravity corrections to the Raychaudhuri equation in the interior of a Schwarzschild black hole and near the classical singularity for several schemes of quantization. We show that the resulting effective equation implies defocusing of geodesics due to the appearance of repulsive terms. This prevents the formation of conjugate points, renders the singularity theorems inapplicable, and leads to the resolution of the singularity for this spacetime.

Effective Raychaudhuri equation and black hole singularity resolution

The study of plasmonics has the potential to reshape the physics of light-matter interactions in metallic nanohybrids and their applications to nanotechnology. Metallic nanohybrids are mode metallic nanoparticles and quantum emitters such as quantum dots. Recently, there is a considerable interest to study the light-matter interaction in the nanoscale size plasmonic nanohybrids. When an external light falls on the QEs, electrons in the QEs get excited from the ground state to the excited states and electron-hole pairs are created in the QEs. Similarly, when the external light (photons) falls on the MNPs it modifies the plasmonic properties of these particles. We know that there are free electrons on the surface of the MNPs. These free electrons oscillate as the charged waves on the surface. The quantized particles of the charged wave are called plasmons. When external light photons fall on the surface of the MNPs, there is an interaction between the photons and plasmons. This interaction produces new types of quantized quasi-particles called the surface plasmon polaritons (SPPs) It interesting to note that exciton energies and SPP energies can be modified by manipulating the size and shape of the QEs. It is also found that exciton and SPP energies can also be modified by applying an external field such as external control lasers, external stress-strain fields, and magnetic fields. Here we study the light-matter interaction in plasmonic nanohybrids made of an ensemble of metallic nanoparticles and quantum emitters. The study of linear and nonlinear plasmonics has the potential to reshape the physics of light-matter interactions and their applications to nanotechnology and nanomedicine. Further, we include the effect of the dipole-dipole interaction (DDI) on the light-matter interaction in plasmonic nanohybrids. We found that the SPP field also induces dipoles in QEs and MNPs and they interact with each other via that the anomalous dipole-dipole interaction. It is shown that the anomalous DDI is many times stronger than the classical DDI. The nonlinear plasmonics such as two-photon spectroscopy and Kerr nonlinearity is also explored. Finally, we have examined that these nanohybrids can be used to fabricate the nanosensors and nano switches for the applications of nanotechnology and nanomedicine.

Light-matter Interaction in Plasmonic Nanohybrids

We study the response of a static Unruh-DeWitt detector outside an exotic compact object (ECO) with a variety of (partially) reflective boundary conditions in 3+1 dimensions. The horizonless ECO, whose boundary is extremely close to the would-be event horizon, acts as a black hole mimicker. We find that the response rate is notably distinct from the black hole case, even when the ECO boundary is perfectly absorbing. For a (partially) reflective ECO boundary, we find resonance structures in the response rate that depend on the different locations of the ECO boundary and those of the detector. We provide a detailed analysis in connection with the ECO's vacuum mode structure and transfer function.

Unruh-DeWitt Detector Differentiation of Black Holes and Exotic Compact Objects

The mass and spin properties of black hole binaries inferred from their gravitational-wave signatures reveal important clues about how these binaries form. For instance, stellar-mass black holes that evolved together from the same binary star will have spins that are preferentially aligned with their orbital angular momentum. Alternatively, if the black holes formed separately from each other and later became gravitationally bound, then there is no such preference for having aligned spins. Furthermore, it is known that the presence of misaligned spins induces a general relativistic precession of the orbital plane, imprinting unique structure onto the gravitational-wave signal. The fidelity with which gravitational-wave detectors can measure off-axis spins, or equivalently, precession, will therefore have important implications for the use of gravitational waves to study binary black hole formation channels. I will summarize a new study that examines how well the A+/AdV+ detector network will measure off-axis spin components, and report preliminary results comparing spin resolution between the fourth and fifth LIGO-Virgo observing runs using simulated detector noise and multiple sets of simulated signals distributed over the mass-spin parameter space.

Prospects for measuring off-axis spins of binary black hole sources with A+/AdV+

Perturbation theory for gravitating quantum systems tends to fail at very late times (a type of perturbative breakdown known as secular growth). We argue that gravity is best treated as a medium/environment in such situations, where reliable late-time predictions can be made using tools borrowed from quantum optics. To show how this works, we study the explicit example of a qubit hovering just outside the event horizon of a Schwarzschild black hole (coupled to a real scalar field) and reliably extract the late-time behaviour for the qubit state. At very late times, the so-called Unruh-DeWitt detector is shown to asymptote to a thermal state at the Hawking temperature.

Hot qubits on the horizon

Spontaneous two-photon decay rates for the $1s2s\;^1S_0$ -- $1s^2\;^1S_0$ transition in helium and its isoelectronic sequence up to $Z$ = 10 are calculated, including the effects of finite nuclear mass. We use correlated variational wave functions in Hylleraas coordinates and pseudostate summations for intermediate states. The accuracy of previous work is improved by several orders of magnitude. Length and velocity gauge calculations agree to eight or more figures, demonstrating that the theoretical formulation correctly takes into account the three effects of (1) mass scaling, (2) mass polarization, and (3) radiation due to motion of the nucleus in the center-of-mass frame [1].

Algebraic relationships are derived and tested relating the expansion coefficients in powers of $\mu/M$, where $\mu/M$ is the ratio of the electron reduced mass to the nuclear mass. Astrophysical applications of two-photon transitions to the continuum emission around 400 $\mu$m in planetary nebulae will be briefly discussed.

[1] A. T. Bondy, D. C. Morton, and G.W.F. Drake, Phys.\ Rev.\ A {\bf 102}, 052807 (2020).

$^*$Research supported by NSERC and by SHARCNET.

Two-photon decay rates in heliumlike ions: finite nuclear mass effects$^*$

First-semester physics labs typically aim to confirm and mirror relationships explored in the lectures. Often using computer-interfaced equipment to measure physical variables, students investigate relationships with time or other variables. We took our move to online delivery in the pandemic as an opportunity to re-think physics labs. We report here a suite of remotely delivered labs developed to introduce scientific attitudes and skills. Emphasized attitudes were collaboration, creativity, perseverance, decision making, communication, and innovation. Skills such as moving from question to hypothesis, spreadsheet basics, linearization, and introductory statistics leveraged simple experiments (time to roll down a ramp, period of a pendulum) into hands-on introductions to scientific tools and ways of thinking. We abandoned the lab manual model, instead requiring students to create plans and communicate their work. Experiment plans included details on the objective/hypothesis, equipment used, experimental setup, detailed procedure of data acquisition, and specifics of data analysis. Sharing created plans occurred before data acquisition. Choosing not to rely on each student having a particular device, we explored kinematics using basic household items, and analysis utilized university-provided Microsoft Excel. Focusing on physics-specific nomenclature (such as uncertainty) gave way to adopting standardized statistical ideas like t-prime comparisons. We believe these labs emphasize attitudes and skills that are more valued across the scientific disciplines than those typically developed in traditional introductory physics labs.

Home-Based Labs to Develop Broadly Applicable Scientific Skills and Attitudes

Resonant laser ionization spectroscopy uses multiple lasers to step-wise excite atom, therefore is a powerful tool for the study of high energy atomic structures, such as Rydberg states and autoionizing states. At the laser ion source test stand (LIS-stand) in TRIUMF, resonant laser ionization spectroscopy is used to study complex atoms. The spectroscopy results not only provide efficient laser ionization schemes for on-line laser ion source beam delivery of these elements but also the information of Rydberg and autoionizing states. This allows also to refine the energy of the ionization potential of these elements as well as extract information on some electron correlations. An overview of the off-line resonant laser ionization spectroscopy at TRIUMF will be presented.

Resonant laser ionization spectroscopy to study Rydberg and autoionizing states

The $^{137}\mathrm{Ba}^+$ ion is a promising candidate for high-fidelity quantum computing. We generate barium atoms using laser ablation of a $\mathrm{BaCl}_2$ target. The flux of neutral atoms generated by ablation is then ionized near our ion trap-center, giving us trapped ions which we can then use for quantum computing. Laser ablation loading can be used to trap ions more quickly and with less added heat load than other common loading methods. Because of the relatively low abundance of the isotope of interest, a two-step photoionization technique is used, which gives us the ability to selectively load a desired isotope. In this talk, I discuss characterization of the ablation process for our $\mathrm{BaCl}_2$ targets, including typical fluences needed, preparation and lifetimes of ablation spots, and plume temperature estimates. We demonstrate loading of single $^{137}\mathrm{Ba}^+$ ions with high selectivity compared to its 11% natural abundance.

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