The rapid rise of central bank digital currency (CBDC) has sparked a heated discussion on
its security, supervision and audit. To this end, this study designs a CBDC system based on …

In this review, I have tried to focus on the development of the field, from the first speculations
to the current lines of research. According to Einstein's theory of general relativity, black …

General relativity is one of the pillars of modern physics. For decades, the theory has been
mainly tested in the weak-field regime with experiments in the solar system and radio …

Einstein's theory of General Relativity predicts that the spacetime metric around
astrophysical black holes is described by the Kerr solution. In this work, we employ state-of …

We analyze simultaneous observations with NuSTAR and Swift of the black hole binary GX
339–4 in which we clearly detect both a strong thermal component and prominent relativistic …

X-ray reflection spectroscopy is a powerful tool for probing the strong gravity region of black
holes and can be used for testing general relativity in the strong field regime. Simplifications …

The presence of spacetime singularities in physically relevant solutions of the Einstein
Equations is normally interpreted as a symptom of the breakdown of classical general …

The continuum-fitting and the iron-line methods are currently the two leading techniques for
measuring the spins of accreting black holes. In the past few years, these two methods have …

Fitting the thermal continuum emission of accreting black holes observed across X-ray
bands represents one of the principle means of constraining the properties (mass and spin) …

ABSTRACT LMC X-1, a persistent, rapidly rotating, extra-galactic, black hole X-ray binary
(BHXB) discovered in 1969, has always been observed in its high soft state. Unlike many …