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A communication scenario is described involving a series of events triggered by a transmitter and observed by a receiver experiencing relativistic time dilation. The message selected by the transmitter is assumed to be encoded in the…

Mathematical Physics · Physics 2021-08-30 Mladen Kovačević

We report a novel radio autocorrelation (AC) search for extraterrestrial intelligence (SETI). For selected frequencies across the terrestrial microwave window (1-10 GHz) observations were conducted at the Allen Telescope Array to identify…

A number of radio interferometers are currently being planned or constructed to observe 21 cm emission from reionization. Not only will such measurements provide a detailed view of that epoch, but, since the 21 cm emission also traces the…

Symbol synchronization refers to the estimation of the start of a symbol interval and is needed for reliable detection. In this paper, we develop a symbol synchronization framework for molecular communication (MC) systems where we consider…

Information Theory · Computer Science 2017-02-24 Vahid Jamali , Arman Ahmadzadeh , Robert Schober

Symbol synchronization refers to the estimation of the start of a symbol interval and is needed for reliable detection. In this paper, we develop several symbol synchronization schemes for molecular communication (MC) systems where we…

Information Theory · Computer Science 2017-09-05 Vahid Jamali , Arman Ahmadzadeh , Robert Schober

We consider interstellar scintillations as a cause of intermittency in radio signals from extraterrestrial intelligence (ETI). We demonstrate that scintillations are very likely to allow initial detections of narrowband signals from distant…

Astrophysics · Physics 2009-10-30 James M. Cordes , T. Joseph W. Lazio , Carl Sagan

Recent technological advances could make interstellar travel possible, using ultra-lightweight sails pushed by lasers or solar photon pressure, at speeds of a few percent the speed of light. Obtaining remote observational data from such…

Instrumentation and Methods for Astrophysics · Physics 2017-11-17 Michael Hippke

The volume of radio-astronomical data is a considerable burden in the processing and storing of radio observations with high time and frequency resolutions and large bandwidths. Lossy compression of interferometric radio-astronomical data…

Instrumentation and Methods for Astrophysics · Physics 2016-11-09 A. R. Offringa

A measurement of the cosmological 21 cm signal remains a promising but as-of-yet unattained ambition of radio astronomy. A positive detection would provide direct observations of key unexplored epochs of our cosmic history, including the…

Cosmology and Nongalactic Astrophysics · Physics 2015-08-18 Morgan Presley , Adrian Liu , Aaron Parsons

Synchronized radio telescope-based experiments conducted since 2017, together with subsequent interferometer experiments, provide evidence of an anomalous source of 3.7 Hz bandwidth pulses, sourced from near the direction of the star Rigel.…

Signal Processing · Electrical Eng. & Systems 2026-04-16 William J. Crilly

Deep, narrow-band Halpha observations taken with the TAURUS Tunable Filter (TTF) on the 4.2m WHT telescope are presented for two nearby radio galaxies with strong jet-cloud interactions. Although the brightest emission line components are…

Astrophysics · Physics 2009-10-31 C. N. Tadhunter , M. Villar-Martin , R. Morganti , J. Bland-Hawthorn , D. Axon

Entanglement has the ability to enhance the transmission of classical information over a quantum channel. However, fully harvesting this advantage typically requires complex entangling measurements, which are challenging to implement and…

We identify a systematic distortion of the gain-vs.-frequency function of radio telescopes caused by digital flattening ("whitening") of the signal's spectrum followed by re-quantization, a common pair of processes in the signal processing…

Instrumentation and Methods for Astrophysics · Physics 2026-05-08 Ruby Byrne , Larry R. D'Addario , Daniel C. Jacobs , Gregg Hallinan

Dispersion in the interstellar medium is a well known phenomenon that follows a simple relationship, which has been used to predict the time delay of dispersed radio pulses since the late 1960s. We performed wide-band simultaneous…

The single-letter characterisation of the entanglement-assisted capacity of a quantum channel is one of the seminal results of quantum information theory. In this paper, we consider a modified communication scenario in which the receiver is…

Quantum Physics · Physics 2024-09-16 Kaiyuan Ji , Bartosz Regula , Mark M. Wilde

This paper presents an observing methodology for calibrated measurements of radio interference levels and compare these with threshold interference limits that have been established for interference entering the bands allocated to the Radio…

Instrumentation and Methods for Astrophysics · Physics 2023-03-01 Willem A. Baan , Axel Jessner , Jaap Steenge

Significant work has been done to develop quantum satellites, which generate entangled pairs in space and distribute them to ground stations separated some distance away. The reverse uplink case, where pairs are generated on the ground and…

Quantum Physics · Physics 2025-06-30 S. Srikara , Hudson Leone , Alexander S. Solnstev , Simon J. Devitt

Pulsars with periods more than 0.4 seconds in the declination range -9o < decj < 42o and in the right ascension range 0h < r.a.< 24h were searched in parallel with the program of interplanetary scintillations monitoring of a large number of…

The sky-averaged, or global, background of redshifted $21$ cm radiation is expected to be a rich source of information on cosmological reheating and reionizaton. However, measuring the signal is technically challenging: one must extract a…

Instrumentation and Methods for Astrophysics · Physics 2016-08-03 Tejaswi Venumadhav , Tzu-Ching Chang , Olivier Doré , Christopher M. Hirata

The 21-cm signal of neutral hydrogen - emitted during the Epoch of Reionization - promises to be an important source of information for the study of the infant universe. However, its detection is impossible without sufficient mitigation of…

Instrumentation and Methods for Astrophysics · Physics 2019-01-09 A. Mouri Sardarabadi , L. V. E. Koopmans