AIP summer meeting 2025

Session

Atomic and Molecular Physics

4 Dec 2025, 10:40

Hope Theatre (Building 40, Room 153)

Conveners

Atomic and Molecular Physics

• Joshua Machacek (Research School of Physics, Australian National University)

Atomic and Molecular Physics

• Julian Berengut (University of New South Wales)

Atomic and Molecular Physics

• Benjamin Roberts (University of Queensland, Australia)

138. Beyond Mean-Field: Modelling Atom Interactions in Compact Rotation Sensors

Jessica Eastman (Australian National University)

04/12/2025, 10:40

Atomic and Molecular Physics

Invited/Keynote talk

Atomic matter-wave interferometers have demonstrated exceptional long-term stability in precision rotation sensing under controlled laboratory conditions [1]. Translating this performance to compact, mobile platforms could revolutionise navigation technologies. Guided matter-wave gyroscopes, which confine ultracold atomic gases in optical potentials, offer a promising route toward...

80. A vibronic approach to the hyperfine interaction observed in biomagnetosensors

Anjay Manian (The University of Wollongong)

04/12/2025, 11:10

Atomic and Molecular Physics

Contributed Oral

The interactions of biological processes with magnetic fields can have significant impacts, with a strong example of this being magnetosensitivity in avian proteins allowing for migration[1]. The two main biological systems for optically-driven magnetosensing are cryptochrome (CRY) and light-oxygen-voltage (LOV) proteins[2,3], where each can be broadly summarised by 4 steps: photoactivation,...

86. Measurement of nuclear charge radius difference in metastable helium isotopes

Kannan Suresh Kumar (Australian National University)

04/12/2025, 11:25

Atomic and Molecular Physics

Contributed Oral

One long-standing puzzle in modern physics is the discrepancy between the most accurate proton charge radius measurements from muonic hydrogen spectroscopy and electronic hydrogen spectroscopy [1]. Despite theoretical improvements over the last decade, the mismatch remains [2], potentially hinting at physics beyond the Standard Model [3].

Helium, the next simplest atom after hydrogen,...

169. Fast and low-loss, all-optical phase modulation in warm rubidium vapour

William O C Davis (Macquarie University)

04/12/2025, 11:40

Atomic and Molecular Physics

Contributed Oral

Low-loss high-speed switches are an integral component of future photonic quantum technologies, with applications in state generation, multiplexing, and the implementation of quantum gates. Phase modulation is one method of achieving this switching; however, existing optical phase modulators, such as Pockels cells and waveguided lithium niobate, offer either high bandwidth or low loss—not...

133. Axion Dark Matter Detection Using Atomic Clocks

Isabella Pham

04/12/2025, 11:55

Atomic and Molecular Physics

Contributed Oral

Axions are a promising dark matter candidate as well as a compelling solution to the strong charge-parity problem. Axion dark matter can be modelled as a background, classical field, whose interactions with Standard Model particles and forces give rise to observable effects. Although there are many experiments that search for these axion-induced experimental observables, given the mystery of...

146. Atomic parity violation and the caesium polarisability puzzle: A possible solution from inseparable contributions to perturbative expansions

Jack Easton (University of Queensland)

04/12/2025, 12:10

Atomic and Molecular Physics

Contributed Oral

The measurement of atomic parity violation in Cs currently provides the most precise test of electroweak theory at low energies. High precision calculations of the Stark-induced 6S-7S vector transition polarisability are required to interpret this measurement and determine the level of agreement with the Standard Model prediction. However, there is currently a 2.8σ discrepancy between values...

121. Accessing higher-order nuclear magnetization moments with muonic atoms

Jacinda Ginges

04/12/2025, 12:25

Atomic and Molecular Physics

Contributed Oral

Little is known about the distribution of magnetization inside the nucleus. While nuclear charge distributions may be well understood through techniques like electron scattering, muonic atom spectroscopy, and precision measurements of atomic isotope shifts, nuclear magnetization distributions are much harder to probe.

We highlight and exploit a property of heavy muonic atoms that enables...

183. Improved differential charge radii of heavy alkali metals using isotope shift

Dr Amy Geddes (University of Queensland)

04/12/2025, 13:40

Atomic and Molecular Physics

Contributed Oral

Isotope shift spectroscopy has repeatedly demonstrated its efficacy in high-precision tests of fundamental physics and the Standard Model. Its ability to benchmark atomic models and determine sizes of atomic nuclei has been well established, and in recent years, it has also been identified as one method for searching for potential dark matter particles.

The isotopic shift in transition...

189. Metastable Helium Atom Production by Positron Impact

Mr Liam Wymer (Research School of Physics, Australian National University)

04/12/2025, 13:55

Atomic and Molecular Physics

Contributed Oral

We have adapted one of the ANU positron beamlines, which use a Surko buffer gas trap and a strong magnetic field, to enable direct measurements of reaction products from atomic collision experiments. An effusive gas jet was added to the beamline, which allowed us to cross a helium beam with the high-resolution, pulsed positron beam. Long-lived (metastable) neutral excited helium atoms formed...

200. Atomic clocks, space-time variation of the fundamental constants and dark matter

Vladimir Dzuba (University of New South Wales)

04/12/2025, 14:10

Atomic and Molecular Physics

Contributed Oral

Fundamental constants—such as the fine-structure constant α, the strong-interaction scale, and particle masses—may vary in an expanding Universe. A spatial variation could help explain apparent fine tuning: we inhabit a region where the values permit life. Hints from quasar absorption spectra suggest a gradient in α, but decisive confirmation requires laboratory tests. Atomic clocks provide...

202. Polarised Positron Interactions with Cold, Polarised Atoms

Matt Best (Research School of Physics, Australian National University)

04/12/2025, 14:25

Atomic and Molecular Physics

Contributed Oral

The positron is the antimatter counterpart of the electron. They can annihilate directly, producing gamma rays (e.g., two 511 keV) or form a bound state known as positronium (Ps). The bound state has two forms: a singlet or para-Ps (125ps lifetime), and a triplet state or ortho-Ps (142ns lifetime). These states decay into a number of gamma rays (even or odd, respectively),which can be measured...

216. Recent Progress in the Ultranarrow Linewidth Multiwatt Diamond Raman Lasers in the Visible

Osama Terra (Macquarie University)

04/12/2025, 14:40

Atomic and Molecular Physics

Contributed Oral

Lasers with ultra-narrow linewidths, stable single-frequency operation, exceptional beam quality, and high power in the visible spectrum are indispensable for applications such as artificial guide star generation and optical lattices in next-generation clocks. Diamond Raman Lasers (DRLs) represent a compelling solution, as they enable access to spectral regions that are otherwise challenging...

221. Demonstration of a photonic time-frequency Fourier transform and temporal double slit

Ankit Papneja (Australian National University)

04/12/2025, 14:55

Atomic and Molecular Physics

Contributed Oral

We present a novel demonstration of an optical memory-based time–frequency Fourier transform (TFFT) using an ensemble of cold 87Rb atoms. Our approach combines two widely studied light–matter interaction protocols, Gradient Echo Memory (GEM) for storage and Electromagnetically Induced Transparency (EIT) for recall, to perform a Fourier transform directly within the atomic medium. Optical...

198. Nuclear Clock and the Search for New Physics

Victor Flambaum (University of New South Wales)

04/12/2025, 16:10

Atomic and Molecular Physics

Invited/Keynote talk

Nuclear Clock and the Search for New Physics
The isomeric transition in 229Th - recently laser-excited by multiple groups [1] - opens a path to a nuclear clock with accuracy competitive with, and potentially exceeding, the best optical atomic clocks. Because the nucleus is well shielded from environmental perturbations, systematic shifts can be intrinsically small; however, the surrounding...

225. Detecting dark matter with atomic systems

Narise Williams (The University of Physics)

04/12/2025, 16:40

Atomic and Molecular Physics

Contributed Oral

The mystery of dark matter (DM) is a long-standing issue in physics, with numerous dedicated experiments returning no confirmed detection. As many direct detection experiments rely on catching a signal of nuclear recoil, these types of experiments are not applicable to many DM models.

Instead, we can utilise the precision that atomic physics allows to search for potential interactions...

227. Coarsening dynamics of a spinor condensate in the broken-axisymmetric phase

April Weyling (The University of Queensland)

04/12/2025, 16:55

Atomic and Molecular Physics

Contributed Oral

Non-equilibrium systems underpin a range of phenomena and can often evolve to form emergent structures. Understanding these fundamental processes advances our grasp of complex physical behaviour, and remains a central challenge of physics. One method to drive a system out of equilibrium is via a quench, such as dropping temperature or applying a magnetic field. If this instantaneous shift is...

239. Probing nuclear structure via hyperfine splittings in Yb-173

Jayden Hasted (The University of Queensland)

04/12/2025, 17:10

Atomic and Molecular Physics

Contributed Oral

Atomic hyperfine structure provides a window into the structure of nuclei. High-precision atomic theory is essential for extracting model-independent nuclear observables from hyperfine measurements – permitting the interrogation of nuclear models. Such studies also allow the testing of atomic structure theory in the nuclear vicinity, which is needed for low-energy searches for new physics...