Over the last century, the construction and discovery of the Standard Model of particle physics has been one of the greatest accomplishments in physics. To explore this new frontier, we built larger and larger colliders utilizing the two charged particles that are easiest to produce and manipulate, the proton and the electron. As we contemplate the future of high energy colliders, the use of these particles fundamentally limits our potential energy reach: the low electron mass due to synchrotron radiation and the proton due to its composite nature. Luckily, the Standard Model provides an alternative: the muon. In this talk, I’ll discuss the challenges and possibilities of a muon collider, and give an overview of recent progress towards making one a reality.

The complex interplay between the quantum degrees of freedom in oxides is known to cause a rich variety of intriguing emergent phenomena. While model Hamiltonians are often used to capture the underlying physics, they could be difficult to solve theoretically. This challenge calls for model-based designs for materials synthesis and measurement controls to experimentally simulate the corresponding behaviors. In this talk, I will review examples from our recent work that exploited this strategy to investigate the correlation-topology interplay in the Hubbard Hamiltonian, metallization of the dipolar spin ice Hamiltonian, and competition between orthogonal magnetic anisotropy. The results showcase the use of symmetry as the guide to implement the key ingredients of the targeted model in the experiment designs, which synergistically combine atomic layering synthesis, single-crystal growth, ultralow-temperature high-field transport measurements, and/or synchrotron x-ray scattering with multi-modal controls. New opportunities enabled by most recent capability advances will be discussed as well.

Symmetry is central to our understanding of natural phenomena. And a Sagnac interferometer, first invented by George Sagnac for the detection of the hypothetical “ether” in the Michelson–Gale experiment [1] a century ago, is intrinsically sensitive to broken time-reversal symmetry (TRS). In this talk, I will first describe a loop-less version of the Sagnac interferometer and microscope that has achieved unprecedented nanoradian level Kerr and Faraday sensitivity even at DC. With this Sagnac technique, I will discuss a few examples of our Sagnac studies of 2D magnetism and superconductivity. In exfoliated Cr2Ge2Te6 (CGT), we report [2] the discovery of intrinsic ferromagnetism in 2D van der Walls crystals, defying the well-known Mermin-Wagner theorem. In epitaxial Bi/Ni bilayer samples, we report [3] the observation of 2D superconductivity that spontaneously breaks TRS, which might have an order parameter with a nonzero phase winding number around the Fermi surface, making it a rare example of a 2D topological superconductor. In the Fe-Chalcogenide superconductor FeTe1−xSex, we found intertwined magnetism and superconductivity in its topological surface state [4]. Additionally, our study on exfoliated FeTe1−xSex flakes indicates the existence of a chiral edge state that may be useful for robust quantum computing (unpublished).

1. “The Effect of the Earth’s Rotation on the Velocity of Light, II” Michelson, A. A.; Gale, Henry G. (1925). Astrophysical Journal. 61: 140.
2. “Discovery of intrinsic ferromagnetism in 2D van der Waals crystals”, Nature, 546, 265-269 (2017).
3. “Time-Reversal-Symmetry-Breaking Superconductivity in Epitaxial Bismuth/Nickel Bilayers”, Science Advances, 3, 3, e1602579 (2017).
4. “Revealing the Origin of Time-Reversal Symmetry Breaking in Fe-Chalcogenide Superconductor FeTe1−xSex”. Physical Review Letters, 130(4):046702 (2023)

In the study of quantum matter, measurements have traditionally been viewed as a means of learning about a system. Measurements can, nevertheless, play a more active role—generating novel quantum phenomena that may be difficult or impossible to realize in measurement-free settings. As an interesting example, I will discuss how measurements can dramatically alter universal properties of quantum systems tuned to a phase transition. I will also highlight a path to experimental realization in analog quantum simulators based on Rydberg atom arrays. Finally, I will describe how these ideas inform optimization of quantum teleportation protocols against imperfections—establishing a long-term quantum science application of ‘measurement-altered quantum criticality’.

The visible world around us is made up of atoms, with protons and neutrons forming the nuclei at their core. Together, protons and neutrons make up most of the mass of everything we see in the universe today, from massive galaxies to individual people. Protons and neutrons themselves are complicated many-body quantum states whose properties are determined by the quarks and gluons that they are comprised of. The quest to understand in detail the structure of protons, neutrons, and nuclei is nothing less that an attempt to answer the questions “What are we made of? What is matter?” The Electron Ion Collider (EIC), to be built by JLab and BNL, will be a unique new machine to collide polarized electrons off polarized protons and light nuclei, providing the capability to study multi-dimensional tomographic images of hadronic matter, and collective effects of gluons in nuclei. In this colloquium I will motivate the physics program at the EIC and the unique new machine and detectors that will be required to answer these fundamental questions.

Fundamental questions in nuclear physics such as, “What is the nature of hot and dense matter?” and “What is the origin of r-process nuclei?” are deeply connected to neutron star observations. In this talk, I will explain how we are answering these questions using a combination of data from nuclear experiments, data from neutron star observations, theoretical models of hot and dense matter, and numerical simulations. Answering these questions demands a level of effort beyond that of a single research group, so I explain how progress is being made through collaborations like the Nuclear Physics for Multi-Messenger Mergers Focused Research Hub. I summarize recent results on both the speed of sound and the composition of dense matter. I show how we are enhancing astrophysical simulations by improving the nuclear physics input. Finally, I show how we are using machine learning to accelerate progress.

Massive stars, by which we mean those stars evolving through all the stable nuclear burning stages, play a fundamental role in the evolution of the Universe. Therefore, a good knowledge of how they evolve is required in order to shed light on many topical subjects like, e.g., the chemical evolution of the galaxies and the nature of the sources of gravitational waves. In the last years three main questions – still debated – rose in the community working on massive stars. They concern (1) the compactness of massive stars at the presupernova stage as an indicator of their explodability, (2) the nature of the remnant after the explosion, and in particular the maximum mass of a stellar black hole, and (3) the so called “Red Supergiant (RSG) problem”, i.e. the lack of observed supernovae associated with the observed most luminous RSGs. In this colloquium I will address these questions by firstly reviewing our current understanding of the presupernova evolution of massive stars.

Under specific conditions, exotic Cooper pairing state can emerge with a non-uniform equilibrium order parameter, possessing a finite center-of-mass momentum. Such spatially dependent order parameters (Δ𝑃(r)) can generically feature variations in either their amplitude or phase — or a combination of both. Utilizing Spectroscopic Imaging Scanning Tunneling Microscopy (SI-STM), we’ve identified two primary PDW states in the iron pnictide superconductor, EuRbFe4As4 (ER-1144), a material that features co-existing superconductivity (Tc ≈ 37 kelvin) and magnetism (Tm ≈ 15 kelvin). In the ferromagnetic superconducting phase, the first type is characterized by a superconducting gap that has a long-range, unidirectional spatial modulation (𝛥𝑃~|𝛥0|cos(Q∙r)) in the absence of any other translational symmetry breaking density-wave orders. The second type features an anisotropic Doppler energy shift in reciprocal space due to the phase winding (𝛥𝑃~|𝛥0|𝑒𝑖Q∙r). In contrast, all the striking features are completely suppressed crossing the magnetic transition. Additionally, both PDW states are also impacted by an out-of-plane external magnetic field, evidenced by the Bogoliubov quasiparticle spectrum imaging. Our findings provide valuable insights into the intricate nature of the PDW states and the interplay between magnetism and superconducting order.

Quantum networks have the potential to support capabilities that are unachievable with classical means alone. Besides quantum cryptographic applications, quantum networks have a variety of scientific uses and can help scale up quantum computers. However, the realization of quantum networks faces formidable challenges which include noise that is inflicted upon quantum states, and loss that is suffered by photons which act as information carriers between distributed quantum information processors. In this talk, I will introduce some of the fundamentals of quantum communication, provide examples of noise and loss in quantum systems with real-world examples, and discuss some of the ways that can help us cope with these challenges. At the end of the talk, I will identify several topics that are of research interest to the quantum networks community.

PRX is published by the American Physical Society, a nonprofit membership society of scientists. Its mission goal is to select around 250 *landmark* papers a year from all fields of physics and showcase them to a broad and multidisciplinary readership.

Is your paper a good match for PRX? Or asked differently, what papers qualify as *landmark* papers?

How do the PRX editors actually select such papers? Are such selections always accurate?

How can you, as an author, navigate PRX’s editorial and peer-review process effectively and get the most out of your interactions with the editors and referees?

I will use the talk to discuss with you how to answer these questions. Many of these questions do not have a black-and-white answer in the case of a single paper. Open-minded, reasoned, and constructive dialogues amongst the authors, the editors, and the referees are key to making each concrete process a meaningful and productive experience, and sometimes even a pleasure, for everyone.

The proton and neutron, known as nucleons, are the fundamental building blocks of all atomic nuclei that make up essentially all the visible matter in the universe, including the stars, the planets, and us. More than 50 years of study has revealed that nucleons are composed of elementary particles called quarks and gluons, whose interactions and dynamics are governed by Quantum Chromodynamics (QCD). However, many profound questions remain. In this talk, I will demonstrate that the newly upgraded CEBAF facility at Jefferson Lab and the future Electron-Ion Collider are two complementary and necessary facilities that are capable of exploring the inner structure of nucleons and nuclei at sub-femtometer distance scale, enabling a new emerging science and technology – Nuclear Femtography. These facilities will help address the most compelling unanswered questions about the elementary building blocks of our visible world, taking us to the next frontier of the Standard Model of physics.

All cells sense and respond to physical and chemical cues in their environments. They accomplish this through signal transduction systems—networks of interacting proteins that detect and interpret specific input signals and control appropriate cellular responses. In bacteria, these systems are found in remarkable numbers within individual organisms and across different bacterial species. They play a central role in regulating basic aspects of microbial physiology and mediate responses to diverse environmental signals. I will describe work in which we have explored the organization and properties of these networks in the particularly well studied and genetically tractable organism Escherichia coli.

Topological quantum computing involves using non-Abelian Majorana zero modes for carrying out error-free fault-tolerant quantum computing. This is the preferred quantum computing platform of Microsoft. I will discuss the current status of the search for non-Abelian Majorana zero modes in solid state systems, discussing both theory and experiment. I will also provide my personal prognosis on what the future holds for the subject.

The collision of extremely dense objects such as neutron stars and black holes provides us with a remarkable laboratory to study the laws of physics in extreme environment. Through the study of merging neutron stars, we learn about gravity, the properties of dense matter, the formation of heavy nuclei (gold, platinum, uranium) and neutrino physics. In this talk, I will review the physical processes at play in neutron star mergers and discuss what numerical simulations of colliding neutron stars tell us about the ways in which these systems can be used to better understand cold nuclear matter and astrophysical nucleosynthesis.