Proposed Ultra-High Sensitivity High-Frequency Gravitational Wave Detector

Abstract

The paper discusses the proposed improvement of a High-Frequency Relic Gravitational Wave (HFRGW) detector designed by Li, Baker, Stephenson and Chen in order to greatly improve its sensitivity. The detector utilizes the Gertsenshtein effect, which introduces the conversion of gravitational waves to electromagnetic (EM) waves in the presence of a static magnetic field (3T to 9T). Such a conversion, in conjunction with the use of sensitive microwave, single photon detectors such as a circuit QED developed by Schoelkopf and Girvin at Yale and/or the Rydberg Atom Cavity Detector, or off-the-shelf detectors, could lead to ultra-high sensitivity HFRGW detection especially when the EM-detection photons are focused at the microwave detectors by fractal-membrane reflectors. Noise sources external to the HFRGW detector will be eliminated by placing a tight mosaic of superconducting tiles (e.g., YBCO) and/or fractal membranes on the interior surface of the detector's cryogenic containment vessel in order to provide a perfect Faraday cage. Internal thermal noise will be eliminated by maintaining the containment vessel at a temperature below 48 mK. A non-microwave-reflecting enterior enclosure, shaped to conform to a high-intensity (10 3 to 10 5 W) continuous microwave Gaussian beam (GB), will reduce any background photon flux (BPF) noise radiated normal to the GB's axis. Such BPF will be further attenuated by a series of non-microwave reflecting baffles forming tunnels to the sensitive microwave detectors on each side of the GB and at right angles to the static magnetic field. There are issues concerning bandwidth that are discussed. A HFGW detector of bandwidth of 1 KHz to 10 KHz in the GHz band may be a reasonable choice. It is concluded that the utilization of the new ultra-high-sensitivity microwave detectors, together with the increased microwave power and magnet intensity will allow for a detection of relic gravitational waves exhibiting amplitudes, A, of the time-varying spacetime strains on the order of 10 -32 to 10 -34 .

Towards a New Era in Gravitational Wave Detection: High Frequency Gravitational Wave Research

“…al., 1984;Servin and Brodin, 2003). The power for such a HFGW beam could be as high as 10 11 -10 12 ergs -1 • Black Hole evaporation: A family of primordial mini Black Holes created during the very early Universe could evaporate through the so-called "graviton degree of freedom" (GDF) producing a HFGW background (Bekenstein, 1973;Hawking, 1975;Carr, 1976;Zeldovich, 1980). A rotating primordial mini Black Hole could have an enhanced GDF radiation.…”

“…Other important technology developments that will serve as upgrades for HFGWs devices will rely on microwave photon detectors capable of being sensitive to one single photon, such as the Quantum Electromagnetic Detection Devices (QED) (Schuster, 2006) which will also help to reduce quantum noise level; and/or the Rydberg Atom Cavity Detector (Baker, Stephenson and Li, 2007). Procedures for detection and data analyses based on Non Demolition Measurements would be also of paramount importance to avoid loss of information (Braginski,, 2007).…”

“…An example of such detector is the one being developed by the joint initiative of GravWave, USA, and the Chongqing University, China, materialized in the Li-Baker Detector (Li, et. al., 2003;Baker, Stephenson and Li, 2007). In this device, a Gaussian beam (GB) passes through a static magnetic field region.…”

“…6 HFGWs are cheaper both in construction and in operation. For the sake of illustration, we refer in the following typical characteristics and cost for reference detectors in the Low, Medium and High frequency bands (Li, Baker, Fang and Stephenson, 2007) The Following list provides GW detector's characteristic length (L), frequency (Freq. ), sensitivity (GW amplitude in change in meters per meter) and cost for the various GW detectors in operation or planned such as ASTROD, LISA (planned Laser Interferometer Space Antenna), LIGO (existing Laser Interferometer Gravitational-wave Observatory) and two versions of the Li-Baker HFGW detector (I-type and II-type Electromagnetic (EM) detector): • ASTROD: L ~ 10 8 km; Freq.…”

Applications of High-Frequency Gravitational Waves to the Global War on Terror

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Some of the statements in the abstract are self-contradictory; it is stated that because of "their ability to pass through all material without attenuation, HFGWs could be utilized for uninterruptible, very lowprobability-of-intercept (LPI), high-bandwidth communications" which is clearly contradictory since the HFGWs must interact with a receiver to be useful.I attempted to clarify this in the attached manuscript as follows:"Although HFGWs do not interact with and are not absorbed by ordinary matter, their presence can be detected by their distortion of spacetime as measured for low-frequency gravitational waves by the Laser Interferometer Gravitational Observatory or LIGO (Abbott, et al, 2008), Virgo (Ballardio, et al, 2001), GEO600 (Hogan, 2008) and for HFGWs by detection photons generated from electromagnetic beams having the same frequency, direction and phase as the HFGWs in a superimposed magnetic field, the LiBaker HFGW Detector (Baker, Stephenson and Li, 2008;Li et al, 2008;Li et al 2009), by the change in polarization they produce in a microwave-guide loop as in the Birmingham University Detector (Cruise and Ingley, 2005) and by other such HFGW detection instruments (Chincarini and Gemme, 2003;Nishizawa et al 2008). None of these effects utilized for detection represent interaction with matter in a way that causes GW absorption, but rather interaction with fields and the detection devices do not attenuate the GWs."

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