Tachyons are theoretical superluminal particles, i.e., faster than light particles. The idea of existence of tachyons comes from Arnold Sommerfeld. Bilaniuk and Sudarshan （1969） published the article ＂Particles bey...Tachyons are theoretical superluminal particles, i.e., faster than light particles. The idea of existence of tachyons comes from Arnold Sommerfeld. Bilaniuk and Sudarshan （1969） published the article ＂Particles beyond the Light Barrier＂ in Physics Today magazine where they analyze the theoretical properties of tachyons. From the tachyon idea I have hypothesized the existence of a Superluminal Parallel Universe constituted by Superluminal Conscious Entities that, like the theoretical tachyons, only can exist at speeds greater than the speed of light. This hypothesis should be subject to scientific inquiry but also to philosophical speculation or spiritual imagination. Later I imagine that the Superluminal Parallel Universe is the Spiritual World thought by theologians and idealistic philosophers. I relate the Superluminal Conscious Entities with Spirits and the Superluminal Parallel Universe comprising infinity of Superluminal Conscious Entities with God, the Universal Spirit, thus being simultaneously Unity and Infinity given that superluminal speed implies non-local, instantaneous connections. I imagine that the material Universe might have emerged from that God, assuming that many Spirits could lose superluminality generating the two classes of substances of the Universe： the class of subluminal particles of matter and the class of luminal particles, like photons. I imagine a Soul as a quasi superluminal entity dropped from a Spirit to animate material entities. The substances of both Universes would have evolved in parallel, with life arising and evolving from the subluminal substance driven by companion Souls. Let＇s also imagine that the natural way of being of Spirits and free Souls is a state similar to conscious dreaming. In this imagination, we all, Souls, would have been a part of God and we all might be again. We all are makers of the Universe. We all might get connected with the Spirits in God to beg for and to receive inspiration.展开更多
The observations of Ultra High Energy Cosmic Rays （UHECR） are renewed, focusing on the energy spectra as measured by HiRes, Telescope Array （TA） and Auger detectors （PAO）. It is found that highest energy Auger s...The observations of Ultra High Energy Cosmic Rays （UHECR） are renewed, focusing on the energy spectra as measured by HiRes, Telescope Array （TA） and Auger detectors （PAO）. It is found that highest energy Auger steepening does not agree with GZK cutoff, which is most probably explained by the nuclei mass composition detected by Auger. At present the difference in mass composition in Auger and HiRes/TA data remains the main unsolved problem of UHECR origin.展开更多
The DArk Matter Particle Explorer （DAMPE） is a satellite-borne, high-energy particle and 3,-ray detector, which is dedicated to indirectly detecting particle dark matter and studying high-energy astrophysics. The fi...The DArk Matter Particle Explorer （DAMPE） is a satellite-borne, high-energy particle and 3,-ray detector, which is dedicated to indirectly detecting particle dark matter and studying high-energy astrophysics. The first results about precise measurement of the cosmic ray electron plus positron spectrum between 25 GeV and 4.6 TeV were published recently. The DAMPE spectrum reveals an interesting spectral softening arount 0.9 TeV and a tentative peak around 1.4 TeV. These results have inspired extensive discussion. The detector of DAMPE, the data analysis, and the first results are introduced. In particular, the physical interpretations of the DAMPE data are reviewed.展开更多
In the centenary year of Einstein's General Theory of Relativity, this paper reviews the current status of gravitational wave astronomy across a spectrum which stretches from attohertz to kilohertz frequencies. Se...In the centenary year of Einstein's General Theory of Relativity, this paper reviews the current status of gravitational wave astronomy across a spectrum which stretches from attohertz to kilohertz frequencies. Sect. 1 of this paper reviews the historical development of gravitational wave astronomy from Einstein's first prediction to our current understanding the spectrum. It is shown that detection of signals in the audio frequency spectrum can be expected very soon, and that a north-south pair of next generation detectors would provide large scientific benefits. Sect. 2 reviews the theory of gravitational waves and the principles of detection using laser interferometry. The state of the art Advanced LIGO detectors are then described. These detectors have a high chance of detecting the first events in the near future. Sect. 3 reviews the KAGRA detector currently under development in Japan,which will be the first laser interferometer detector to use cryogenic test masses. Sect. 4 of this paper reviews gravitational wave detection in the nanohertz frequency band using the technique of pulsar timing. Sect. 5 reviews the status of gravitational wave detection in the attohertz frequency band, detectable in the polarisation of the cosmic microwave background, and discusses the prospects for detection of primordial waves from the big bang. The techniques described in sects. 1–5 have already placed significant limits on the strength of gravitational wave sources. Sects. 6 and 7 review ambitious plans for future space based gravitational wave detectors in the millihertz frequency band. Sect. 6 presents a roadmap for development of space based gravitational wave detectors by China while sect. 7 discusses a key enabling technology for space interferometry known as time delay interferometry.展开更多
The covariant entropy bound conjecture is an important hint for the quantum gravity, with several versions available in the literature. For cosmology, Ashtekar and Wilson-Ewing ever show the consistence between the lo...The covariant entropy bound conjecture is an important hint for the quantum gravity, with several versions available in the literature. For cosmology, Ashtekar and Wilson-Ewing ever show the consistence between the loop gravity theory and one version of this conjecture. Recently, He and Zhang [J. High Energy Phys. 10 (2007) 077] proposed a version for the dynamical horizon of the universe, which validates the entropy bound conjecture for the cosmology filled with perfect fluid in the classical scenario when the universe is far away from the big bang singularity. However, their conjecture breaks down near big bang region. We examine this conjecture in the context of the loop quantum cosmology. With the example of photon gas, this conjecture is protected by the quantum geometry effects as expected.展开更多
文摘Tachyons are theoretical superluminal particles, i.e., faster than light particles. The idea of existence of tachyons comes from Arnold Sommerfeld. Bilaniuk and Sudarshan （1969） published the article ＂Particles beyond the Light Barrier＂ in Physics Today magazine where they analyze the theoretical properties of tachyons. From the tachyon idea I have hypothesized the existence of a Superluminal Parallel Universe constituted by Superluminal Conscious Entities that, like the theoretical tachyons, only can exist at speeds greater than the speed of light. This hypothesis should be subject to scientific inquiry but also to philosophical speculation or spiritual imagination. Later I imagine that the Superluminal Parallel Universe is the Spiritual World thought by theologians and idealistic philosophers. I relate the Superluminal Conscious Entities with Spirits and the Superluminal Parallel Universe comprising infinity of Superluminal Conscious Entities with God, the Universal Spirit, thus being simultaneously Unity and Infinity given that superluminal speed implies non-local, instantaneous connections. I imagine that the material Universe might have emerged from that God, assuming that many Spirits could lose superluminality generating the two classes of substances of the Universe： the class of subluminal particles of matter and the class of luminal particles, like photons. I imagine a Soul as a quasi superluminal entity dropped from a Spirit to animate material entities. The substances of both Universes would have evolved in parallel, with life arising and evolving from the subluminal substance driven by companion Souls. Let＇s also imagine that the natural way of being of Spirits and free Souls is a state similar to conscious dreaming. In this imagination, we all, Souls, would have been a part of God and we all might be again. We all are makers of the Universe. We all might get connected with the Spirits in God to beg for and to receive inspiration.
文摘The observations of Ultra High Energy Cosmic Rays （UHECR） are renewed, focusing on the energy spectra as measured by HiRes, Telescope Array （TA） and Auger detectors （PAO）. It is found that highest energy Auger steepening does not agree with GZK cutoff, which is most probably explained by the nuclei mass composition detected by Auger. At present the difference in mass composition in Auger and HiRes/TA data remains the main unsolved problem of UHECR origin.
基金supported by the National Key Research and Development Program of China (Grant No. 2016YFA0400200)the National Natural Science Foundation of China (Grant Nos. 11722328, 11773075, and U1738205)+1 种基金the 100 Talents Program of Chinese Academy of Sciencesthe Youth Innovation Promotion Association of Chinese Academy of Sciences (Grant No. 2016288)
文摘The DArk Matter Particle Explorer （DAMPE） is a satellite-borne, high-energy particle and 3,-ray detector, which is dedicated to indirectly detecting particle dark matter and studying high-energy astrophysics. The first results about precise measurement of the cosmic ray electron plus positron spectrum between 25 GeV and 4.6 TeV were published recently. The DAMPE spectrum reveals an interesting spectral softening arount 0.9 TeV and a tentative peak around 1.4 TeV. These results have inspired extensive discussion. The detector of DAMPE, the data analysis, and the first results are introduced. In particular, the physical interpretations of the DAMPE data are reviewed.
基金supported by the US National Science Foundation(Grant No.PHY-0757058)supported by the National Natural Science Foundation of China(Grant Nos.11443008 and 11503003)+2 种基金a Returned Overseas Chinese Scholars Foundation grant,and Fundamental Research Funds for the Central Universities(Grant No.2015KJJCB06)supported by the National Space Science Center,Chinese Academy of Sciences(Grant Nos.XDA04070400 and XDA04077700)Partial supports from the National Natural Science Foundation of China(Grant Nos.11305255,11171329 and 41404019)
文摘In the centenary year of Einstein's General Theory of Relativity, this paper reviews the current status of gravitational wave astronomy across a spectrum which stretches from attohertz to kilohertz frequencies. Sect. 1 of this paper reviews the historical development of gravitational wave astronomy from Einstein's first prediction to our current understanding the spectrum. It is shown that detection of signals in the audio frequency spectrum can be expected very soon, and that a north-south pair of next generation detectors would provide large scientific benefits. Sect. 2 reviews the theory of gravitational waves and the principles of detection using laser interferometry. The state of the art Advanced LIGO detectors are then described. These detectors have a high chance of detecting the first events in the near future. Sect. 3 reviews the KAGRA detector currently under development in Japan,which will be the first laser interferometer detector to use cryogenic test masses. Sect. 4 of this paper reviews gravitational wave detection in the nanohertz frequency band using the technique of pulsar timing. Sect. 5 reviews the status of gravitational wave detection in the attohertz frequency band, detectable in the polarisation of the cosmic microwave background, and discusses the prospects for detection of primordial waves from the big bang. The techniques described in sects. 1–5 have already placed significant limits on the strength of gravitational wave sources. Sects. 6 and 7 review ambitious plans for future space based gravitational wave detectors in the millihertz frequency band. Sect. 6 presents a roadmap for development of space based gravitational wave detectors by China while sect. 7 discusses a key enabling technology for space interferometry known as time delay interferometry.
基金Supported by the National Natural Science Foundation of China under Grant No. 11175019the Fundamental Research Funds for the Central Universities
文摘The covariant entropy bound conjecture is an important hint for the quantum gravity, with several versions available in the literature. For cosmology, Ashtekar and Wilson-Ewing ever show the consistence between the loop gravity theory and one version of this conjecture. Recently, He and Zhang [J. High Energy Phys. 10 (2007) 077] proposed a version for the dynamical horizon of the universe, which validates the entropy bound conjecture for the cosmology filled with perfect fluid in the classical scenario when the universe is far away from the big bang singularity. However, their conjecture breaks down near big bang region. We examine this conjecture in the context of the loop quantum cosmology. With the example of photon gas, this conjecture is protected by the quantum geometry effects as expected.
