GPS and the Search for Axions

GPS, an excellent tool for geodesy, may serve also particle physics. In the presence of Earth’s magnetic field, a GPS photon may be transformed into an axion. The proposed experimental setup involves the transmission of a GPS signal from a satellite to another satellite, both in low orbit around the Earth. To increase the accuracy of the experiment, we evaluate the influence of Earth’s gravitational field on the whole quantum phenomenon. There is a significant advantage in our proposal. While the geomagnetic field B is low, the magnetized length L is very large, resulting into a scale (BL)2 orders of magnitude higher than existing or proposed reaches. The transformation of the GPS photons into axion particles will result in a dimming of the photons and even to a “light shining through the Earth” phenomenon.

Imprints of ultralight axions on the gravitational wave and pulsar timing measurement

The axion or axion-like particle motivated from a natural solution of strong CP problem or string theory is a promising dark matter candidate.We study the new observational effects of ultralight axion-like particles by the space-borne gravitational wave detector and the radio telescope.Taking the neutron star-black hole binary as an example,we demonstrate that the gravitational waveform could be obviously modified by the slow depletion of the axion cloud around the black hole formed through the superradiance process.We compare these new effects on the binary with the well-studied effects from dynamical friction with dark matter and dipole radiation in model-independent ways.Finally,we discuss the constraints from LIGO/Virgo and study the detectability of the ultralight axion particles at LISA and TianQin.

High-frequency microwave cavity design for high-mass dark matter axion searches

The haloscope based on the TM_(010)mode cavity is a well-established technique for detecting QCD axions.However,the method has limitations in detecting high-mass axion due to significant volume loss in the high-frequency cavity.Utilizing a higher-order mode cavity can effectively reduce the volume loss of the high-frequency cavity.The rotatable dielectric pieces as a tuning mechanism can compensate for the degradation of the form factor of the higher-order mode.Nevertheless,the introduction of dielectric causes additional volume loss.To address these issues,this paper proposes a novel design scheme by adding a central metal rod to the higher-order mode cavity tuned by dielectrics,which improves the performance of the haloscope due to the increased effective volume of the cavity detector.The superiority of the novel design is demonstrated by comparing its simulated performance with previous designs.Moreover,the feasibility of the scheme is verified by the full-wave simulation results of the mechanical design model.

Dynamical interactions of dark energy and dark matter:Yang-Mills condensate and QCD axions

We analyze a model of cold axion dark matter weakly coupled with a dark gluon condensate, reproducing dark energy. We first review how to recover the dark energy behavior using the functional renormalization group approach, and ground our study in the properties of the effective Lagrangian, to be determined non-perturbatively. Then, within the context of GSM×SU（2）D×U（1）PQ, we consider Yang-Mills condensate （YMC） interactions with QCD axions. We predict a transfer of dark energy density into dark matter density, that can be tested in the next generation of experiments dedicated to dark energy measurements. We obtain new bounds on the interactions between the Yang-Mills condensate and axion dark matter from Planck data：the new physics interaction scale related to the axion/gluon condensate mixing is constrained to be higher than the 106 GeV energy scale.

Thermodynamics of warm axionic Abelian gauge inflation

Inflationary spectral index from the Langevin equation is calculated under the frame of warm inflationary scenario with inflaton interacting with U(1) gauge fields through the Chern–Simons coupling ∝ФF_(μv)F^(μv). Under the strong dissipative condition, the spectral index is calculated in terms of the ratio of Hubble parameter to temperature H/T. Then relation between H/T and other cosmic parameters is analytically expressed, based on which a spectral index related to the Chern–Simons coupling strength is further obtained. Numerical results show that cosmic temperature T closes to a constant during inflation and decreases after inflation without a reheating process. Meanwhile, the ratio H/T tends to a constant if the gauged coupling constant is less than a threshold. This phenomenon shows that cosmic temperature may be an important physical parameter with a special value and adiabatic approximation still holds. We obtain the estimate H/T ≤ 0.3377 during inflation from Planck data and other constraint conditions.

5d过渡金属氧化物—Weyl半金属奇异量子物性研究

绝缘体系统的拓扑量子行为是当前物理学领域的焦点。那么没有能隙的金属体系是否也有拓扑非平庸行为呢?答案是肯定的,5d过渡金属元素既有着大的自旋轨道耦合,又有着不可忽略的电子关联作用,由其构成的材料体系因而具有奇异的量子物性。本文先简介人们最近关注的几类5d材料,着重讨论烧绿石结构铱(Ir)氧化物(A2Ir2O7,其中A=Y或稀土元素)。我们通过第一性原理计算结合有效模型成功地预言了这一大类磁阻挫材料的基态磁构型,并预言A2Ir2O7是Weyl半金属。我们发现和拓扑绝缘体一样,作为一种新型拓扑量子态,Weyl半金属态也具有其拓扑性质:Weyl点是受拓扑保护稳定的;Weyl半金属有着受拓扑保护的表面态,即非闭合的费米面(Fermi arc);它对外场的响应也由其拓扑性质决定(只与Weyl点的位置有关,和能带的细节无关)。我们进一步预言尖晶石结构锇(Os)氧化物(AOs2O4,其中A=Ca或Sr)是有着特别磁电响应的Axion绝缘体。最后我们讨论了电子关联、自旋轨道耦合、磁序结构对钙态矿结构锇氧化物的影响,进一步确定NaOsO3是由磁序导致金属–绝缘体相变的Slater绝缘体。

A LN2-based cooling system for a next-generation liquid xenon dark matter detector

In recent years, cooling technology for liquid xenon(LXe) detectors has advanced driven by the development of dark matter(DM) detectors with target mass in the 100–1000 kg range. The next generation of DM detectors based on LXe will be in the 50,000 kg(50 t)range requiring more than 1 k W of cooling power. Most of the prior cooling methods become impractical at this level.For cooling a 50 t scale LXe detector, a method is proposed in which liquid nitrogen(LN2) in a small local reservoir cools the xenon gas via a cold finger. The cold finger incorporates a heating unit to provide temperature regulation. The proposed cooling method is simple, reliable, and suitable for the required long-term operation for a rare event search. The device can be easily integrated into present cooling systems, for example the ‘‘Cooling Bus’ ’employed for the Panda X I and II experiments. It is still possible to cool indirectly with no part of the cooling or temperature control system getting in direct contact with the clean xenon in the detector. Also, the cooling device can be mounted at a large distance, i.e., the detector is cooled remotely from a distance of 5–10 m. The method was tested in a laboratory setup at Columbia University to carry out different measurements with a small LXe detector and behaved exactly as predicted.

Search for topological defect of axionlike model with cesium atomic comagnetometer

Many terrestrial experiments have been designed to detect domain walls composed of axions or axionlike particles(ALPs), which are promising candidates of dark matter. When the domain wall crosses over the Earth, the pseudoscalar field of ALPs could couple to the atomic spins. Such exotic spin-dependent couplings can be searched for by monitoring the transient-in-time change of the atomic spin precession frequency in the presence of a magnetic field. We propose here a single-species cesium atomic comagnetometer, which measures the spin precession frequencies of atoms in different ground-state hyperfine levels, to eliminate the common-mode magnetic-field variations and search for the exotic nonmagnetic couplings solely between protons and ALPs. With the single-species atomic comagnetometer, we experimentally rule out the possibility that the decay constant of the linear pseudoscalar couplings of ALPs to protons is fp■ 3.71 ×107 Ge V. The advanced system has the potential to constrain the constant to be fp■ 10.7 × 109 Ge V, promising to improve astrophysical constraint level by at least one order of magnitude. Our system could provide a sensitive detection method for the global network of optical magnetometers to search for exotic physics.

5d过渡金属氧化物中的奇异量子物性研究

相比于3d和4d过渡金属元素,5d过渡金属元素既具有很强的自旋轨道耦合相互作用,同时它们的电子关联作用也不可忽略.因而5d过渡金属氧化物体系具有许多奇异的量子特性.这篇综述主要介绍我们在5d过渡金属氧化物中的一些理论进展.首先介绍烧绿石结构铱氧化物(A_2Ir_2O_7,A=Y或稀土元素)中的Weyl拓扑半金属性.我们确定出A_2Ir_2O_7这一类具有阻挫结构材料的磁基态,并预言其是Weyl半金属;其Weyl点受到拓扑保护而稳定,而且它的表面态在费米能级形成特别的费米弧.其次预言尖晶石结构锇氧化物(AOs_2O_4,A=Ca,Sr)是具有奇异磁电响应的Axion绝缘体;然后分析了电子关联、自旋轨道耦合对钙钛矿结构的锇氧化物(NaOsO_3)的影响,并成功定出它的基态磁构型,最终确定其为Slater绝缘体.最后介绍了LiOsO_3中铁电金属性的成因.

Hypothetical Dark Matter/Axion Rockets: And the Neutrinos without SUSY Problem

We present Dark Matter candidates from non SUSY processes, in a way emphasizing how a Dark Matter (DM) candidate of roughly 100 - 400 GeV could be formed. As has been said about the Photon rocket and Axions rockets, the presence of a magnetic field supposedly would switch DM particle candidates to photons, in such a way as to in the end configure a photon rocket style device from DM in a thrust chamber. The presence of Dark Matter (DM) would in itself merely indicate that the emerging photon thrust would be comparatively greater than it would be for more conventional photon rockets. This amplifies and improves upon a so called axion rocket ram jet for interstellar travel. We assume that much the same sort of methodology for a would-be axion ramjet could be employed for DM, with perhaps greater thrust/power conversion efficiencies.

Can Thermal Input from a Prior Universe Account for Relic Graviton Production and Imply Usage of the Bogomolnyi Inequality, as a Bridge between Brane World Models and Loop Quantum Gravity in Early Universe Conditions?

The author uses a low temperature and low entropy pre inflation state to create a bridge between String theory and loop quantum gravity. We use this analysis in lieu of the CMB barrier as of z = 1000 since it is our way to come up with a working model of quintessence scalar fields, which permits relic generation of dark matter and dark energy. Not only referencing this bridge, we do it in such a way as to utilize the low entropy condition which the Brane world model of Randal and Sundrum creates, and to show how it is in common with what Caroll and Chen wrote up in 2005., i.e. when the universe was about 1000 times smaller and 100,000 times younger than today.

Does a Randall-Sundrum Brane World Effective Potential Influence Axion Walls Helping to Form a Cosmological Constant Affecting Inflation?

In 2003, Guth posed the following question in a KITP seminar in UCSB. Namely “Even if there exist 101000 vacuum states produced by String theory, does inflation produce overwhelmingly one preferred type of vacuum states over the other possible types of vacuum states”? This document tries to answer how a preferred vacuum state could be produced, and by what sort of process. We construct a di quark condensate leading to a cosmological constant in line with known physical observations. We use a phase transition bridge from a tilted washboard potential to the chaotic inflationary model pioneered by Guth which is congruent with the slow roll criteria. This permits criteria for initiation of graviton production from a domain wall formed after a transition to a chaotic inflationary potential. It also permits investigation of if or not axion wall contributions to inflation are necessary. If we reject an explicit axion mass drop off to infinitesimal values at high temperatures, we may use the Bogomolnyi inequality to rescale and reset initial conditions for the chaotic inflationary potential. Then the Randall-Sundrum brane world effective potential delineates the end of the dominant role of di quarks, and the beginning of inflation. And perhaps answers Freeman Dysons contention that Graviton production is unlikely given present astrophysical constraints upon detector systems. We end this with a description in the last appendix entry, Appendix VI, as to why, given the emphasis upon di quarks, as to the usefulness of using times before Planck time interval as to modeling our physical system and its importance as to emergent field structures used for cosmological modeling.

Effects of phosphorus doping on the physical properties of axion insulator candidate EuIn_(2)As_(2)

We report an investigation on the single crystal growth,magnetic and transport properties of Eu In_(2)(As_(1-x)P_(x))_(2(0≤x≤1).The physical properties of axion insulator candidate Eu In;As;can be effectively tuned by P-doping.With increasing x,the c-axis lattice parameter decreases linearly,the magnetic transition temperature gradually increases and ferromagnetic interactions are enhanced.This is similar to the previously reported high pressure effect on Eu In_(2)As_(2).For x=0.40,a spin glass state at T_(g)=10 K emerges together with the observations of a butter-fly shaped magnetic hysteresis and slow magnetic behavior.Besides,magnetic transition has great influence on the charge carriers in this system and negative colossal magnetoresistance is observed for all P-doped samples.Our findings suggest that Eu In_(2)(As_(1-x)P_(x))_(2) is a promising material playground for exploring novel topological states.

The Efficiency of CP-Violating <i>α</i>2-Dynamos from Primordial Cosmic Axion Oscillation with Torsion

Recently torsion fields were introduced in CP-violating cosmic axion a2-dynamos [Garcia de Andrade, Mod Phys Lett A, (2011)] in order to obtain Lorentz violating bounds for torsion. Here instead, oscillating axion solutions of the dynamo equation with torsion modes [Garcia de Andrade, Phys Lett B (2012)] are obtained taking into account dissipative torsion fields. Magnetic helicity torsion oscillatory contribution is also obtained. Note that the torsion presence guarantees dynamo efficiency when axion dynamo length is much stronger than the torsion length. Primordial axion oscillations due to torsion yield a magnetic field of 109 G at Nucleosynthesis epoch. This is obtained due to a decay of BBN magnetic field of 1015 G induced by torsion. Since torsion is taken as 10–20 s–1, the dynamo efficiency is granted over torsion damping. Of course dynamo efficiency is better in the absence of torsion. In the particular case when the torsion is obtained from anomalies it is given by the gradient of axion scalar [Duncan et al., Nuclear Phys B 87, 215] that a simpler dynamo equation is obtained and dynamo mechanism seems to be efficient when the torsion helicity, is negative while magnetic field decays when the torsion is positive. In this case an extremely huge value for the magnetic field of 1015 Gauss is obtained. This is one order of magnitude greater than the primordial magnetic fields of the domain wall. Actually if one uses tDW ~ 10-4 s one obtains BDW ~ 1022 G which is a more stringent limit to the DW magnetic primordial field.

Extra Dimensions, Brane Worlds, and the Vanishing of Axion Contributions to Inflation

We examine from first principles the implications of the 5th Randall Sundrum Brane world dimension in terms of setting initial conditions for chaotic inflationary physics. Our model pre-supposes that the inflationary potential pioneered by Guth is equivalent in magnitude in its initial inflationary state to the effective potential presented in the Randall-Sundrum model. We also consider an axion contribution to chaotic inflation (which may have a temperature dependence) which partly fades out up to the point of chaotic inflation being matched to a Randall-Sundrum effective potential. If we reject an explicit axion mass drop off to infinitesimal values at high temperatures, we may use the Bogomolnyi inequality to re-scale and reset initial conditions for the chaotic inflationary potential. One of the potential systems embedded in the Randall-Sundrum brane world is a model with a phase transition bridge from a tilted washboard potential to the chaotic inflationary model pioneered by Guth which is congruent with the slow roll criteria. If, as written up earlier, the axion wall contribution is due to di-quarks, which is equivalent to tying in baryogenesis to the formation of chaotic inflation initial conditions, with the Ran-dall-Sundrum brane world effective potential delineating the end of the dominant role of di-quarks, and the beginning of inflation.

Effective Field Theory Techniques Applied to the Properties of the Axion

We utilize the effective field theory approach to study the properties of the axion. In particular, with s as well as u and d quarks regarded to be relatively light we derive a formula for the mass of the axion; a rough estimate of the rate for its dominant decay mode at low energy is also carried out.

An Axion Interpretation of the ANITA Events

We suggest that the unusual events observed by the ANITA experiment originate from axion particles traversing the Earth. Under the influence of the geomagnetic field, the axion may oscillate into a photon and vice-versa. To amplify the axion transition into photon, we consider that the phenomenon takes place at resonance, where the effective photon mass is equal to the axion mass. This requirement fixes the axion mass at 44 eV. An axion at this mass scale reproduces the cold dark matter scenario. If our interpretation prevails, with the help of axions we can establish an axion tomography of the Earth.

NASA’s EM Drive Thrust from the Forces of the Quantum Vacuum of Spacetime

Building on the various manifestations of the forces latent in the quantum vacuum of spacetime such as Hawking’s radiation and Unruh temperature, we resolve a major paradox connected to an immensely important proposal by NASA scientists for constructing a practically fuelless spacecraft. In a nutshell, preliminary laboratory work shows that NASA’s electromagnetic drive project is viable and several experiments and measurements show it is real. Yet the proposal violates a fundamental principle of classical mechanics, namely Newton’s third law. The resolution of this paradox is quite straight forward in principle. It is simply the case that although the proposal seems to be based on classical mechanics and classical thinking it is only superficially so. Deep at the roots, the EM drive proposal of NASA is not classical physics but rather based on the vacuum forces of quantum cosmology and the theory of dark energy density of the universe. In fact the proposal is deeply linked to Hawking’s radiation and Unruh temperature, which is explained in some detail in the main body of the present short paper within the frame work of E-infinity Cantorian spacetime theory and D. Gross’ Heterotic superstring theory. In short the quintessence of our explanation is to regard the EM drive as a quasi electromagnetic cavity with an effective event horizon akin to that of a Hawking black hole emitting radiation causing ultimately the needed thrust to push the spacecraft forwards. In addition and by invoking fractal spacetime self similarity we show that a spacecraft will be subject to another cosmic thrust on the large scale of the entire cosmos.

来自外星球——五十铃雅仕(AXION)

它是概念车。 这是看到那辆车的直观印象。 的确,它像极了概念车,甚至有一点天外来客的味道,高科技、眩目,很容易联想到传说中的外星球,那种高智慧和文明的产物。然而它的确是一款地道的量产车,并且销量极佳。它就是五十铃雅仕(AXION)全功能豪化越野车。

Quantum calculation of axion-photon transition in electromagnetodynamics for cavity haloscope

The Witten effect implies the presence of electric charge of magnetic monople and the possible relationship between axion and dyon.The axion-dyon dynamics can be reliably built based on the quantum electromagnetodynamics(QEMD)which was developed by Schwinger and Zwanziger in the 1960's.A generic low-energy axionphoton effective field theory can also be realized in the language of“generalized symmetries”with higher-form symmetries and background gauge fields.In this work,we implement the quantum calculation of the axion-single photon transition rate inside a homogeneous electromagnetic field in terms of the new axion interaction Hamiltonian in QEMD.This quantum calculation can clearly imply the enhancement of conversion rate through resonant cavity in axion haloscope experiments.We also show the promising potentials on the cavity search of new axion-photon couplings.