Welcome!

This is the website for Online Workshops and Conferences organized by the Institute for Quantum Studies at Chapman University during the coronavirus pandemic.

This is a workshop for IQS members who are ordinarily resident at Chapman University to keep each other up to date about the research we have been doing during the pandemic. It will also serve as a test of the technology that may be used for larger conferences and workshops in the future.

All Chapman faculty, postdocs and students may join the talks, but it will not be widely advertised outside the IQS community. Talks will be held over Zoom and the URL to join is:

https://chapman.zoom.us/j/99960768815

The Zoom meeting will have a “waiting room” and the host has to let you in to the main meeting. This is to prevent Zoom bombings.

• Cristhiano Duarte: Quantum agency… but also quantum networks, many-quantum physics and coarse-graining: the many facets of my work
  • In this seminar, I will walk you through the many different research projects I am involved in. My plan consists of giving you a glimpse of the papers we have recently put out, and also to talk about the concept of quantum agents – my main ongoing project. For the former, I will be focusing on (i) an original method to determine whether or not certain covariance matrices are compatible with the topology of a given quantum network, (ii) violations of Bell-inequalities in many-body quantum systems, and (iii) how the very concept of agreement can be used to describe coarse-grained dynamics. For the latter, I will try to justify why the recent approach to quantum Markovianity championed by K. Modi can be useful to design the concept of a genuinely quantum agent. Being realistic, I do know it is too much for 60min. So, if you get captured by any of these topics, I am sure we can find time to chat during the week.

• Armen Gulian: Recent months scientific activities at Advanced Physics Laboratory of IQS in Burtonsville, MD
  • I will talk on recent scientific articles we submitted during this pandemic season which summarize previously performed experiments and theoretical developments. Future plans will also be briefly sketched out.

• Lorenzo Catani: Towards a new ontological framework for quantum theory
  • No-go theorems (Bell, Kochen-Specker, Spekkens, …) formally show the departure of quantum theory from classical theory. These are formulated adopting the ontological model’s framework, also known as hidden variable model’s framework, and characterize quantum theory with problematic (“fine-tuned”) properties. I will argue that the lesson to take from no-go theorems is to abandon the ontological model’s framework as the way to model reality. I will analyze what I believe to be the unnatural assumptions of such framework and I will propose a way to change it. The basic principle of the new notion of reality I propose is that for something to exist is for something to be recorded. I will motivate the principle and explore its consequences. In order to implement such proposal into a precise theory-independent mathematical framework I will make use of point-free topological spaces (locales). I will discuss why this new proposal should be promising for understanding quantum theory and I will present several open questions.

• Ismael de Paiva: Vector potential with complex components in post-selected systems
  • In this talk, I will discuss the Aharonov-Bohm effect in the presence of a quantized source of magnetic field. In this scenario, if the source has a relatively small uncertainty while the particle encircles it, the final state of the joint system can be approximated as a tensor product between the initial state of the source with the expected final state of a charge encircling a region with the average magnetic field generated by the source. Moreover, if a post-selection of the source is considered, the effective magnetic vector potential may be complex-valued. Some consequences of this result are presented.

• Cai Waegell: An Attempt at a Local Quantum Theory
  • Having spent the past six months exploring all sorts of possible machinery for a local theory of quantum mechanics, I will introduce one model that seems particularly promising. This model has many orthogonal states embedded on a single space-time, where each state describes the kinematic motion of a pseudo-fluid of point objects, each of which obeys the restrictions of special relativity. The key conceptual deviations from standard quantum theory is that we will replace the wavefunction in configuration space with a set of indexed orthogonal fields for each fundamental system in space-time. This can be done as almost a direct mapping from the SE for multiple particles, but it requires that coupling potentials can only act locally, which is to say that two objects can only interact if they are at the same event. The role of coupling potentials it to perform a matched unitary transform between the different orthogonal fields for a pair of objects at a single event. Orthogonality is determined by the set of distinct outcomes for the coupling – always a list of different ways to conserve the same physical quantity during the interaction.

• Matt Leifer: Uncertainty from the Aharonov-Vaidman Identity
  • In this talk, I show how the Aharonov-Vaidman identity $A|\psi\rangle = \langle A \rangle |\psi\rangle + \Delta A |\psi^{\perp}_A\rangle$ can be used to prove relations between the standard deviations of observables in quantum mechanics. In particular, it offers a more direct and less abstract proof of the Robertson uncertainty relation $\Delta A \Delta B \geq \frac{1}{2} \left \vert \left \langle \left [ A,B \right ] \right \rangle \right \vert$ than the textbook proof based on the Cauchy-Schwartz inequality. I discuss the relationship between these two proofs and show how the Cauchy-Schwartz inequality can be derived from the Aharonov-Vaidman identity. I give Aharonov-Vaidman based proofs of several other uncertainty relations that have appeared in the literature and I show how the Aharonoov-Vaidman identity can be used to handle propagation of uncertainty in quantum mechanics.