Given a quantum state, how can we tell how "quantum" it is? That is, can we use that quantum state to do kick-start an interesting protocol like quantum teleportation, or is it really just a classical state in disguise? Quantum coherence tries to answer this question by quantifying the amount of superposition present in a quantum state. We develop some new easy-to-compute methods of...
Resource theories have been widely used in quantum information as a framework for quantifying quantum resources, even of remarkably different types. However, the applicability of such a framework is far more general than quantum theory, given that its mathematical underpinning lies in category theory, which is a universal paradigm in math. In this way, resource theories can be extended beyond...
To effectively operate a large-scale quantum computer, it is essential to thoroughly and confidently assess the performance of its components.
The gold standard for performance assessment of quantum gates is randomised benchmarking.
In particular, randomised benchmarking of universal qutrit quantum gates is needed.
In this presentation I will show how we advance from qubit dihedral...
It is well known that repeated projective measurements can either slow down (the Zeno effect) or speed up (the anti-Zeno effect) quantum evolution. Until now, studies of these effects for a two-level system interacting with its environment have focused on repeatedly preparing the excited state via projective measurements. In this paper, we consider the repeated preparation of an arbitrary...
The production of very energetic quarks and gluons (i.e., partons) and their showering in the Quantum Chromodynamical (QCD) vacuum has been well studied inside relativistic electron-proton and proton-(anti)proton collisions. Our good understanding of high energy partons in those collisions allow us to consider them as calibrated probes inside relativistic heavy-ion collisions, where they are...
The study of rare B- decays provides a unique opportunity to probe the Standard Model and search for signs of new physics. In particular, the VLQs (iso-singlet down-type), characterized by their isospin singlet nature, can play a significant role in these rare decays. We investigate the impact of the VLQ on the B → sμ+μ- decay process, starting by reviewing the theoretical framework of the...
The Equation of State (EOS) has a pretty long history. The physics behind it should be explored. The main purpose of the EOS is to yield the volume of a given material system under given external temperature and mechanical condition. Since the predicted volume is fixed, the EOS is for the system in a macroscopic equilibrium state. In such a situation, the Macroscopic Mechanical Equilibrium...
Natural orbitals are defined as the eigenvectors one-body reduced density matrix. These orbitals are a highly convergent basis for the many-body problem. Here, some exact properties of the natural orbitals are discussed, particularly their similarities and differences for excited states with varying energy differences. These results are used to justify the behavior of entanglement...
It is known that Schwarzchild geometry exhibits thermodynamic properties and these have a statistical mechanics explanation. An interesting question to ask is if we can study the statistical mechanics of spins on this background. In this presentation we will answer this question in the positive and construct an Ising-like model on black hole space. Then we will numerically study the...
I will discuss the role of partition dominance ordering in the expression of coincidence rates in the interference of partially distinguishable fermions, and also discuss the algorithmic complexity of various functions entering in the expressions of these rates.
As one of the fundamental concepts in physics, degrees of freedom are commonly encountered in classical mechanics, statistical physics, and QFT. However, the concept is often introduced without a careful explanation. In this talk, I will present a pedagogical approach to understanding degrees of freedom by analyzing simple (but not trivial!) mechanical systems. We will emphasize the role...
Land-use decision-making processes have a long history of producing globally pervasive systemic equity and sustainability concerns. Quantitative, optimization-based planning approaches, e.g., Multi-Objective Land Allocation (MOLA), seemingly open the possibility to improve objectivity and transparency by explicitly evaluating planning priorities by land use type, amount, and location. Here, we...
We describe a case of indeterminacy in general relativity for homogeneous and isotropic cosmologies for a class of dark energy fluids. The cosmologies are parametrized by an equation of state variable, with one instance giving the same solution as Norton’s mechanical dome. Our example goes beyond previously studied cases in that indeterminacy lies in the evolution of spacetime itself: the...
Recently, significant process has been made in the understanding of how two apparent horizons merge to become one during a black hole collision. Apparent horizons are examples of more general objects called marginally outer trapped surfaces (MOTS) and as an offshoot of the merger studies, we have learned that MOTS are much more common than had been previously realized. For example, apart from...
The Schwarzschild solution admits one parameter, the mass, which can be positive or negative. What is the meaning of the negative mass solution? Negative mass is an intriguing idea. Negative mass, to be physical, must satisfy the dominant energy condition. Indeed stable configurations can be found that correspond to bubbles of negative mass, however crucially, in a background energy density....
Exact solutions of the Einstein equations describing black holes in cosmological backgrounds exhibit time-dependent masses over Hubble times. We report tentative evidence for such a cosmological coupling obtained by studying populations of supermassive black holes in a sequence of red elliptical galaxies spanning 9 billion years. If black holes are non-singular, they typically have de Sitter...
Gravitational solitons are globally stationary, geodesically complete spacetimes with positive energy. These event-horizonless geometries do not exist in the electrovacuum by the classic Lichnerowicz Theorem. However, gravitational solitons exist when there are non-Abelian gauge fields in higher dimensions. In this talk, I will present a new class of supersymmetric asymptotically globally...
In general, black holes interact with
external matter and fields. A four-dimensional static black hole
within a static external axisymmetric gravitational field can be
described by a Weyl solution of the Einstein equations. These results
can be extended to higher dimensions using the generalized Weyl form.
Various studies have been devoted to investigate the properties of the
distorted...
The spacetime M in general relativity (GR) is curved. Parallel transportations of vectors in M depend on path. This leads to the fact that vectors distributed on different points in M can not be added up to get a sum vector unambiguously. Geometry does not allow talking about matter energy momentum distributed on (passing through) a finite or infinite spacelike (timelike) hypersurface, does...
Alice is taking a course on QFT in curved spacetime, and accidentally drops her midterm into a black hole. From Hawking's famous calculation, she suspects the midterm been irreversibly thermalized, and her GPA with it. Her colleague Bob, a card-carrying unitarian, believes the midterm can be recovered from the Hawking radiation, at least in principle. Their mutual friend Charlotte is a...
Abstract:
The main goal of this research is to obtain a clear and accurate model of the late-time behavior of a quantum-corrected black hole’s radiative emission wave. Specifically, the focus is on late-time tail waveforms, which appear after the exponentially damped signal originating from the ring down phase of a perturbed black hole. This project focused on interpreting the effects of...
Extracting the physics of cosmological inhomogeneities and anisotropies from full quantum gravity is a crucial step to make contact with observations. I address this problem within the group field theory (GFT) formalism for quantum gravity by studying the perturbative mean-field effective dynamics of small relational inhomogeneities of GFT condensates. I show how these perturbations give rise...
We derive a “classical-quantum” approximation scheme for a broad class of bipartite quantum systems. In this approximation, one subsystem’s evolution is governed by classical equations of motion with quantum corrections, and the other subsystem evolves quantum mechanically with equations of motion informed by the classical degrees of freedom. Similar approximations are common when discussing...