M. M. Sheikh-Jabbari
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View article: On the Analysis Dependence of DESI Dynamical Dark Energy
On the Analysis Dependence of DESI Dynamical Dark Energy Open
We continue scientific scrutiny of the DESI dynamical dark energy (DE) claim by explicitly demonstrating that the result depends on the analysis pipeline. Concretely, we define a likelihood that converts the w0waCDM model back into the (fl…
View article: A New Derivation of Classical Gravitational Second Law of Thermodynamics
A New Derivation of Classical Gravitational Second Law of Thermodynamics Open
It is established that black holes have entropy and behave as thermodynamical systems. Associating entropy to gravitational fields has not remained limited to black holes, necessitating the notion of the second law of thermodynamics in gra…
View article: Freelance holography, part II: Moving boundary in gauge/gravity correspondence
Freelance holography, part II: Moving boundary in gauge/gravity correspondence Open
We continue developing the freelance holography program, formulating gauge/gravity correspondence where the gravity side is formulated on a space bounded by a generic timelike codimension-one surface inside AdS and arbitrary boundary condi…
View article: Crosschecking Cosmic Distances from DESI BAO and DES SNe Points to Systematics
Crosschecking Cosmic Distances from DESI BAO and DES SNe Points to Systematics Open
We perform a consistency check of DESI DR2 BAO constraints ($D_M/r_d, D_H/r_d)$ by reconstructing the same quantities from DES supernovae (SNe) in bins with the same effective redshift $z_{\textrm{eff}}$. We find that the ratio of $D_M/r_d…
View article: Freelance holography, part I: Setting boundary conditions free in gauge/gravity correspondence
Freelance holography, part I: Setting boundary conditions free in gauge/gravity correspondence Open
We explore AdS/CFT duality in the large N limit, where the duality reduces to gauge/gravity correspondence, from the viewpoint of covariant phase space formalism (CPSF). In particular, we elucidate the role of the W, Y , and Z fre…
View article: Does DESI 2024 confirm ΛCDM?
Does DESI 2024 confirm ΛCDM? Open
View article: Strings, Virasoro sandwiches and worldsheet horizons
Strings, Virasoro sandwiches and worldsheet horizons Open
We revisit the canonical quantization of free bosonic closed string theory and observe that the physicality of states requires vanishing of the worldsheet Virasoro algebra generators sandwiched between any two physical states. This require…
View article: The CosmoVerse White Paper: Addressing observational tensions in cosmology with systematics and fundamental physics
The CosmoVerse White Paper: Addressing observational tensions in cosmology with systematics and fundamental physics Open
View article: Do high redshift QSOs and GRBs corroborate JWST?
Do high redshift QSOs and GRBs corroborate JWST? Open
View article: DESI and SNe: dynamical dark energy, Ω<i>m</i> tension or systematics?
DESI and SNe: dynamical dark energy, Ω<i>m</i> tension or systematics? Open
Dark Energy Spectroscopic Instrument (DESI) observations have led to statistically significant dynamical dark energy (DDE) claims. Noting that there is a mild DDE signal in DESI BAO alone, but no DDE signal in DESI FS galaxy clustering alo…
View article: Further support for <i>S</i>8 increasing with effective redshift
Further support for <i>S</i>8 increasing with effective redshift Open
We previously reported an increasing trend in $S_8$ with effective redshift $z_{\textrm {eff}}$ based on $f \sigma _8(z)$ constraints over the redshift range $0 \lesssim z \lesssim 2$. Recently, independent studies presenting data that ali…
View article: Towards quantizing null p-branes: light-cone gauge analysis and physical Hilbert space
Towards quantizing null p-branes: light-cone gauge analysis and physical Hilbert space Open
A bstract We study null p -branes, p -branes with a Carrollian p +1-dimensional worldvolume embedded in a generic D -dimensional flat Minkowski target space. This theory has a generalised BMS p +1 gauge symmetry. By fixing the light-cone g…
View article: Revisiting Quantization of Gauge Field Theories: Sandwich Quantization Scheme
Revisiting Quantization of Gauge Field Theories: Sandwich Quantization Scheme Open
Quantization of field theories with gauge symmetry is an extensively discussed and well-established topic. In this short note, we revisit this old problem. The gauge degrees of freedom have vanishing momenta, and hence their equations of m…
View article: Implications of DES 5YR SNe Dataset for $$\Lambda $$CDM
Implications of DES 5YR SNe Dataset for $$\Lambda $$CDM Open
Dark Energy Survey 5-year supernovae data (DES 5YR SNe) in conjunction with Planck CMB and Dark Energy Spectroscopic Instrument (DESI) BAO data has detected a strong dynamical dark energy (DE) deviation from the $$\Lambda $$ CDM model. H…
View article: Freelance Holography, Part II: Moving Boundary in Gauge/Gravity Correspondence
Freelance Holography, Part II: Moving Boundary in Gauge/Gravity Correspondence Open
We continue developing the freelance holography program, formulating gauge/gravity correspondence where the gravity side is formulated on a space bounded by a generic timelike codimension-one surface inside AdS and arbitrary boundary condi…
View article: Charges in general relativity and black hole thermodynamics
Charges in general relativity and black hole thermodynamics Open
We shed a new light on the long-standing problem of covariant charges in diffeomorphism invariant theories such as general relativity by noting the other important feature of the theory, the background independence. To this end, we develop…
View article: A comparison of Bayesian and frequentist confidence intervals in the presence of a late Universe degeneracy
A comparison of Bayesian and frequentist confidence intervals in the presence of a late Universe degeneracy Open
Hubble tension is a problem in one-dimensional (1D) posteriors, since local $$H_0$$ determinations are only sensitive to a single parameter. Projected 1D posteriors for $$\Lambda $$ CDM cosmological parameters become more non-Gaussia…
View article: Big Bang in dipole cosmology
Big Bang in dipole cosmology Open
We continue the study of dipole cosmology framework put forward in Krishnan et al. (JCAP 07:020, 2023), a beyond FLRW setting that has a preferred direction in the metric which may be associated with a cosmological tilt, a cosmic dipole. I…
View article: Do High Redshift Qsos and Grbs Corroborate Jwst?
Do High Redshift Qsos and Grbs Corroborate Jwst? Open
View article: Towards Quantizing Null p-branes: Light-Cone Gauge Analysis and Physical Hilbert Space
Towards Quantizing Null p-branes: Light-Cone Gauge Analysis and Physical Hilbert Space Open
We study null $p$-branes, $p$-branes with a Carrollian $p+1$-dimensional worldvolume embedded in a generic $D$-dimensional flat Minkowski target space. This theory has a generalized BMS$_{p+1}$ gauge symmetry. By fixing the light-cone gaug…
View article: DESI and SNe: Dynamical Dark Energy, $Ω_m$ Tension or Systematics?
DESI and SNe: Dynamical Dark Energy, $Ω_m$ Tension or Systematics? Open
Dark Energy Spectroscopic Instrument (DESI) observations, when combined with Cosmic Microwave Background (CMB) and Type Ia supernovae (SNe), have led to statistically significant dynamical dark energy (DDE) claims. In this letter we recons…
View article: Further support for $S_8$ increasing with effective redshift
Further support for $S_8$ increasing with effective redshift Open
In Adil et al. 2023, we reported an increasing trend in $S_8$ with effective redshift $z_{\textrm{eff}}$ based on $f σ_8(z)$ constraints over the redshift range $0 \lesssim z \lesssim 2$, and predicted that this trend would be observable i…
View article: Strings, Virasoro Sandwiches and Worldsheet Horizons
Strings, Virasoro Sandwiches and Worldsheet Horizons Open
We revisit the canonical quantization of free bosonic closed string theory and observe that the physicality of states requires vanishing of the worldsheet Virasoro algebra generators sandwiched between any two physical states. This require…
View article: Covariant phase space formalism for fluctuating boundaries
Covariant phase space formalism for fluctuating boundaries Open
A bstract We reconsider formulating D dimensional gauge theories, with the focus on the case of gravity theories, in spacetimes with boundaries. We extend covariant phase space formalism to the cases in which boundaries are allowed to fluc…
View article: ΛCDM Tensions: Localising Missing Physics through Consistency Checks
ΛCDM Tensions: Localising Missing Physics through Consistency Checks Open
ΛCDM tensions are by definition model-dependent; one sees anomalies through the prism of ΛCDM. Thus, progress towards tension resolution necessitates checking the consistency of the ΛCDM model to localise missing physics either in redshift…
View article: Charges in General Relativity and Black Hole Thermodynamics
Charges in General Relativity and Black Hole Thermodynamics Open
We shed a new light on the longstanding problem of covariant charges in diffeomorphism invariant theories like General Relativity (GR) by noting the other important feature of the theory, the background independence. To this end, we develo…
View article: Covariant Phase Space Formalism for Fluctuating Boundaries
Covariant Phase Space Formalism for Fluctuating Boundaries Open
We reconsider formulating $D$ dimensional gauge theories, with the focus on the case of gravity theories, in spacetimes with boundaries. We extend covariant phase space formalism to the cases in which boundaries are allowed to fluctuate. W…
View article: Gravitational stress tensor and current at null infinity in three dimensions
Gravitational stress tensor and current at null infinity in three dimensions Open
We develop the framework that reveals the intrinsic conserved stress tensor and current associated with the null infinity of a three-dimensional (3d) asymptotically flat spacetime. These are, respectively, canonical conjugates of degenerat…
View article: Towards a realistic dipole cosmology: the dipole ΛCDM model
Towards a realistic dipole cosmology: the dipole ΛCDM model Open
Dipole cosmology is the maximally Copernican generalization of the FLRW paradigm that can incorporate bulk flows in the cosmic fluid. In this paper, we first discuss how multiple fluid components with independent flows can be realized in t…
View article: Implications of DES 5YR SNe Dataset for $Λ$CDM
Implications of DES 5YR SNe Dataset for $Λ$CDM Open
Dark Energy Survey five-year supernovae data (DES 5YR SNe) in conjunction with Planck CMB and Dark Energy Spectroscopic Instrument (DESI) BAO data has detected a strong dynamical dark energy (DE) deviation from the $Λ$CDM model.Here we shi…