Tootfinder

Klein-Gordon theory in noncommutative phase space
Shi-Dong Liang
https://arxiv.org/abs/2403.09075 https://arxiv.org/pdf/2403.09075

Klein-Gordon theory in noncommutative phase space
We extend the three-dimensional noncommutative relations of the positions and momenta operators to those in the four dimension. Using the Bopp shift technique, we give the Heisenberg representation of these noncommutative algebras and endow the noncommutative parameters associated with the Planck constant, Planck length and cosmological constant. As an analog with the electromagnetic gauge potential, the noncommutative effect can be interpreted as an effective gauge field, which depends on the …

Happy Easter friends!
My stats from yesterday's #cycling loop.
It's been a really nice 2.5h out in the sun. Lots of head wind in one direction but also nice tailwind on the way back.
The photo is taken at the #sylvenstein reservoir with Lot's of

The saga of Z the escaped Zebra continues! The way this keeps coming up in local news is great. Heard last night about some hikers running away from it, getting out of the way, and then seeing someone on a mountain bike a moment later who said they were trying to chase the Zebra down, now this.
Z looks transfixed seeing the horse riders, wondering what fate befell it's fellow equines.
Video ripped from bird site, found on thestranger.com

This https://arxiv.org/abs/2402.00634 has been replaced.
link: https://scholar.google.com/scholar?q=a

High-resolution momentum distributions from low-resolution wave functions
Nucleon momentum distributions calculated with a common one-body operator vary with the resolution scale (and scheme) of the Hamiltonian used. For high-resolution potentials such as Argonne $v_{18}$ (AV18) there is a high-momentum tail, reflecting short-range correlations in the nuclear wave function, which is reduced or absent for softer, lower-resolution interactions. We explore if the similarity renormalization group (SRG) can be used to quantitatively reproduce the high-resolution distribut…

🎉 Reflecting on key milestones today! From 2 years of weekly blogging to my daughter's school graduation—life's full of big moments. Read more here: [Link] 🎓✍️ #Milestones #FamilyLife #BloggingJourney

Life’s Milestones: Embracing Changes and New Opportunities – Bob Mueller
Reflecting on milestones in blogging and family life, from weekly post streaks to celebrating school graduations and new chapters in life

Measuring the Lense-Thirring precession and the neutron star moment of inertia with pulsars
Huanchen Hu, Paulo C. C. Freire
https://arxiv.org/abs/2403.18785

Measuring the Lense-Thirring precession and the neutron star moment of inertia with pulsars
Neutron stars (NSs) are compact objects that host the densest forms of matter in the observable universe, providing unique opportunities to study the behaviour of matter at extreme densities. While precision measurements of NS masses through pulsar timing have imposed effective constraints on the equation of state (EoS) of dense matter, accurately determining the radius or moment of inertia (MoI) of a NS remains a major challenge. This article presents a detailed review on measuring the Lense-T…

This https://arxiv.org/abs/2401.00791 has been replaced.
initial toot: https://mastoxiv.page/@arXiv_mat…

Normal operators for momentum ray transforms, I: The inversion formula
The momentum ray transform $I_m^k$ integrates a rank $m$ symmetric tensor field $f$ on $\mathbb R^n$ over lines with the weight $t^k$, $I_m^kf(x,ξ)=\int_{-\infty}^\infty t^k\langle f(x+tξ),ξ^m\rangle\,\mathrm{d}t$. We compute the normal operator $N_m^k=(I_m^k){}^*I_m^k$ and present an inversion formula recovering a rank $m$ tensor field $f$ from the data $(N_m^0f,\dots,N_m^mf)$.

This https://arxiv.org/abs/2402.00584 has been replaced.
link: https://scholar.google.com/scholar?q=a

Arellano-Bond LASSO Estimator for Dynamic Linear Panel Models
The Arellano-Bond estimator is a fundamental method for dynamic panel data models, which is widely used in practice. However, the estimator is severely biased when the data's time series dimension $T$ is long due to the large degree of overidentification. We propose a simple two-step approach to remove the bias. First, apply LASSO to the cross-section data at each time period to select the most informative moment conditions, using lagged values of suitable covariates. Second, apply a linear ins…

This https://arxiv.org/abs/2306.14960 has been replaced.
initial toot: https://mastoxiv.page/@arXiv_hepp…

Parton Distributions from Boosted Fields in the Coulomb Gauge
We propose a new method to calculate parton distribution functions (PDFs) from lattice correlations of boosted quarks and gluons in the Coulomb gauge. Compared to the widely used gauge-invariant Wilson-line operators, these correlations greatly simplify the renormalization thanks to the absence of linear power divergence. Besides, they enable access to larger off-axis momenta under preserved 3D rotational symmetry, as well as enhanced long-range precision that facilitates the Fourier transform.…

Columbia University President announces decision to arrest student protestors.
#ColumbiaUniversity #FreePalestine #NYC #NewYorkCity
Fwd: Addressing Unfolding Events on Campus
Thu, Apr 18 at 1:28PM
- Forwarded message - From: Minouche Shafik <officeofthepresident@columbia.edu> Date: Thu, Apr 18, 2024 at 13:22
Subject: Addressing Unfolding Events on Campus
To: <PRESIDENT@lists.columbia.ed>
To the Columbia University community:
This morning. I had to make a decision that I hoped would never be necessary. I have always said that the safety of our community was my top priority and that we needed to preserve an environment where everyone could learn in a supportive context. Out of an abundance of concern for the safety of Columbia's campus, I authorized the New York Police Department to begin clearing the encampment from the South Lawn of Morningside campus that had been set up by students in the early hours of Wednesday morming.
I took this extraordinary step because these are extraordinary circumstances. The individuals who established the encampment violated a long list of rules and policies. Through direct conversations and in writing, the university provided multiple notices of these violations. including a written warning at 7:15 p.m. on Wednesday notifying students who remained in the encampment as of 9:00 p.m. that they would face suspension pending investigation. We also tried through a number of channels to engage with their concerns and offered to continue discussions if they agreed to disperse
I regret that all of these attempts to resolve the situation were rejected by the students involved. As a result, NYPD officers are now on campus and the process of clearing the encampment is underway.
Protests have a storied history at Columbia and are an essential component of free speech in America and on our campus. We work hard to balance the rights of students to express political views with the need to protect other students from rhetoric that amouits to harassment and discrimination. We updated our protest policy to allow demonstrations on very short notice and in prime locations in the middle of campus while still allowing students to get to class, and fabs and libraries to operate. The current encampment violates all of the new policies, severely disrupts campus life, and creates a harassing and intimidating environment for many of our students
Columbia is committed to academic freedom and to the opportunity for students and faculty to engage in political expression—within established rules and with respect for the safety of all. The policies we have in place around demonstrations are in place to support both the right to expression and the safety and functioning of our university.
Prior to taking this action. I complied with the requirements of Section 444 of the University Statutes.
This is a challenging moment and these are steps that I deeply regret having to take. I encourage us all to show compassion and remember the values of empathy and respect that draw us together as a Columbia comnminity.
Sincerely,
Minouche Shafik
President, Columbia University in the City of New York