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334 scholarly results for stat.AP
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The collection of scholarly papers presents diverse advancements across different realms of applied physics and quantum mechanics. Faxian Cao's critique on the self-localization of ad-hoc arrays using time differences highlights methodological and typographical improvements, emphasizing ongoing dialogue for enhancing research robustness. Argenti et al. delve into attosecond transient absorption spectroscopy, revealing new ultrafast resonant phenomena in helium and validating theoretical predictions with experimental data, thus advancing electronic quantum control. Karpa and Dulieu propose utilizing ultracold interactions between ions and polar molecules to mitigate collisional losses, potentially revolutionizing control in quantum simulations and cold quantum chemistry. Lastly, Czachor's exploration of noncanonical field quantization challenges conventional quantum optics by reinterpreting vacuum structure and blackbody radiation, suggesting observable deviations under specific conditions. Together, these works contribute significantly to their respective fields by introducing innovative methodologies and theoretical insights, sparking further research and technological applications.
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arxiv.org Β· scholarly article
Concerns for Self-Localization of Ad-Hoc Arrays Using Time Difference of Arrivals
Faxian Cao
2024 arXiv Open Access
This document presents some insights and observations regarding the paper that was published in IEEE Transactions on Signal Processing (TSP), titled "Self-Localization of Ad-Hoc Arrays Using Time Difference of Arrivals". In the spirit of constructive feedback, I wish to highlight two key areas of consideration. The first pertains to aspects related to methodology, experimental results, and statements made in the paper. The second part addresses specific equation/typographical errors. This work aims to initiate a constructive dialogue concerning certain aspects of the paper published in IEEE TSP. Our intention is to provide feedback that contributes to the ongoing improvement of the paper's robustness and clarity.
arxiv.org Β· scholarly article
Attosecond Transient Absorption Spectroscopy of doubly-excited states in helium
Luca Argenti; Christian Ott; Thomas Pfeifer; Fernando MartΓ­n
2012 arXiv Open Access
Strong-field manipulation of autoionizing states is a crucial aspect of electronic quantum control. Recent measurements of the attosecond transient absorption spectrum of helium dressed by a few-cycle visible pulse [Ott et al., arXiv:1205.0519[physics.atom-ph] ] provide evidence of novel ultrafast resonant phenomena, namely, two-photon Rabi oscillations between doubly-excited states and the inversion of Fano profiles. Here we present the results of accurate \emph{ab-initio} calculations that agree with these observations and in addition predict that (i) inversion of Fano profiles is actually periodic in the coupling laser intensity and (ii) the supposedly dark $2p^2$ {$^1$S} state also appears in the spectrum. Closer inspection of the experimental data confirms the latter prediction.
arxiv.org Β· scholarly article
Ultracold Interactions between Ions and Polar Molecules
Leon Karpa; Olivier Dulieu
2024 arXiv Open Access DOI: 10.1103/7zz8-qk2c
We propose a platform for observing and controlling the interactions between atomic ions and a quantum gas of polar molecules in the ultracold regime. This approach is based on the combination of several recently developed methods in two so-far complementary research domains: ion-atom collisions and studies of ultracold polar molecules. In contrast to collisions between ions and ground-state atoms, which are dominated by losses due to three-body recombination (TBR) already at densities far below those typical for quantum degenerate ensembles, our proposal makes use of polar molecules, their rich level structure, and sensitivity to electric fields to design effective interaction potentials where ion-neutral TBR losses and molecule-molecule losses due to sticky collisions could be strongly suppressed. This may open a broad range of applications including precise control of collisional properties in molecular ensembles using ions, quantum simulations, and cold quantum chemistry between polyatomic molecules.
arxiv.org Β· scholarly article
(Noncanonical) field quantization by means of a single harmonic oscillator
Marek Czachor
2000 arXiv Open Access DOI: 10.1088/0305-4470/33/45/307
The paper is an extension of quant-ph/9912102. The new framework is tested on the 2-photon spontaneous emission and blackbody radiation. The new effects are rather subtle. The probability of the 2-photon emission is shown to consist of a product of several terms: One which is identical to this from standard quantum optics and the remaining ones formally resembling detector inefficiencies (here arising from nontrivial vacuum structure). The blackbody distribution is indistinguishable from the Planck law for T<T_{critical} but for T>T_{critical} the maximum of the distribution gets lowered and shifts towards higher frequencies. T_{critical} is a parameter that, in principle, should be observable. No normal ordering of operators is needed and vacuum energy is nonzero but finite. Vacuum is represented by a subspace spanned by ground states of the oscillators and is not equivalent to the cyclic vector of the GNS construction. The non-CCR algebra is discussed in more detail.
arxiv.org Β· scholarly article
Climbing the rotational ladder to chirality
Alec Owens; Andrey Yachmenev; Sergei N. Yurchenko; Jochen KΓΌpper
2018 arXiv Open Access DOI: 10.1103/PhysRevLett.121.193201
Molecular chirality is conventionally understood as space-inversion-symmetry breaking in the equilibrium structure of molecules. Less well known is that achiral molecules can be made chiral through extreme rotational excitation. Here, we theoretically demonstrate a clear strategy for generating rotationally-induced chirality (RIC): An optical centrifuge rotationally excites the phosphine molecule (PH$_3$) into chiral cluster states that correspond to clockwise ($R$-enantiomer) or anticlockwise ($L$-enantiomer) rotation about axes almost coinciding with single P-H bonds. Application of a strong dc electric field during the centrifuge pulse favors the production of one rotating enantiomeric form over the other, creating dynamically chiral molecules with $permanently$ oriented rotational angular momentum. This essential step toward characterizing RIC promises a fresh perspective on chirality as a fundamental aspect of nature.
arxiv.org Β· scholarly article
Granularity Noise Limit in Atomic-Ensemble-Based Metrology
Chen-Rong Liu; Chuang Li; Runxia Tao; Yixuan Wang; Mingti Zhou; Xinqing Wang; Ying Dong
2026 arXiv Open Access
Conventional noise analysis in atomic-ensemble sensing assumes a continuous-medium approximation, thereby treating the atomic system as a deterministic dielectric. Here, we demonstrate that this assumption breaks down due to the discrete, particulate nature of the ensemble, giving rise to an intrinsic "atomic granularity noise" (AGN) that fundamentally competes with the optical measurement noise (OMN, typically photon shot noise). By introducing a discrete-atom statistical framework, we derive a unified noise-scaling law governed by a single dimensionless resource ratio, $\mathcal{R} = \bar{N}_{\mathrm{ph}}/\bar{N}_{\mathrm{at}}$ at (the photon-to-atom flux ratio). This law predicts a continuous crossover from an OMN-limited regime to an AGN-limited regime. Crucially, our results reveal a counter-intuitive constraint for sensor optimization: increasing optical probe power -- standard practice to mitigate OMN -- can paradoxically degrade sensitivity by driving the system into the AGN-dominated regime. Furthermore, we identify a critical resource threshold, $\mathcal{R}_{\mathrm{crit}}$, beyond which quantum-enhanced metrology using non-classical light fails to improve sensitivity, as it becomes limited by the AGN.
arxiv.org Β· scholarly article
Nonideal strongly magnetized plasmas of neutron stars and their electromagnetic radiation
A. Y. Potekhin; G. Chabrier; D. Lai; W. C. G. Ho; M. van Adelsberg
2005 arXiv Open Access DOI: 10.1088/0305-4470/39/17/S21
We study the equation of state, polarization and radiation properties for nonideal, strongly magnetized plasmas which compose outer envelopes of magnetic neutron stars. Detailed calculations are performed for partially ionized hydrogen atmospheres and for condensed hydrogen or iron surfaces of these stars. This is a companion paper to astro-ph/0511803
arxiv.org Β· scholarly article
Application of Optical Stochastic Cooling in Future Accelerator Light Sources
Xiujie Deng
2024 arXiv Open Access
In this paper, we propose to combine two promising research topics in accelerator physics, i.e., optical stochastic cooling (OSC) and steady-state microbunching (SSMB). The motivation is to provide a powerful radiation source which could benefit fundamental science research and industry applications. Our study shows that such a compact OSC-SSMB storage ring using present technology can deliver EUV light with an average power of kilowatt, and spectral flux $>10^{20}$ phs/s/0.1\%b.w., which is four orders of magnitude higher than existing synchrotron sources. It is expected that the presented work is of value for the development of both OSC and SSMB.
arxiv.org Β· scholarly article
Comment On the Connection Between Planets, Dark Matter and Cancer, by Hector Socas-Navarro (arXiv:1812.02482 [physics.med-ph])
Konstantin Zioutas; Edward Valachovic; Marios Maroudas
2018 arXiv Open Access DOI: 10.1142/S1793048019200029
In arXiv:1812.02482 Socas-Navarro (SN) provided multiple confirmation of the claimed 88 days melanoma periodicity. This greatly strengthens the observation by Zioutas and Valachovic (ZV). Here we comment on the work by SN, because it objects the interpretation of the observation by ZV. Notice that SN objection is based on serious assumptions, which were explicitly excluded by ZV. Further, the conclusion made with a sub-set of data (4 percent) is statistically not significant to dispute ZV. On the contrary, since the same periodicity appears also in other 8 major cancer types, we consider it as a global oscillatory behaviour of cancer. At this stage, such a rather ubiquitous cancer periodicity makes any discussion of a small subset of data at least secondarily. Further, we show here that the 88 days Melanoma periodicity is not related to solar activity. Planetary lensing of streaming low speed invisible massive particles remains the only viable explanation, as it has been introduced previously with a number of physics observations [4]. We also show that planetary lensing of low speed particles cannot be considered in isolation, because of the dominating Sun gravity, at least for the inner planets. Interestingly, gravitational lensing - deflection favours low speed particles.
arxiv.org Β· scholarly article
An infection-responsive collagen-based wet-spun textile fibre for wound monitoring
Jonathon Gorman; Charles Brooker; Xinyu Li; Giuseppe Tronci
2025 arXiv Open Access
Wound infections are a significant clinical and socioeconomic challenge, contributing to delayed healing and increased wound chronicity. To enable early infection detection and inform therapeutic decisions, this study investigated the design of pH-responsive collagen fibres using a scalable wet spinning process, evaluating product suitability for textile dressings and resorbable sutures. Type I collagen was chemically functionalised with 4-vinylbenzyl chloride, enabling UV-induced crosslinking and yielding mechanically robust fibres. Bromothymol blue, a halochromic dye responsive to pH changes, was incorporated via drop-casting to impart visual infection-responsive colour change. Gravimetric analysis and Fourier Transform Infrared Spectroscopy confirmed high dye loading, whereby a Loading Efficiency of 99+/-3 wt.% was achieved. The fibres exhibited controlled swelling in aqueous environments (Swelling Ratio: 323+/-79 - 492+/-73 wt.%) and remarkable wet-state Ultimate Tensile Strength (UTS: 12+/-3 - 15+/-7 MPa), while up to ca. 30 wt.% of their initial crosslinked mass was retained after 24 hours in a collagenase-rich buffer (pH 7.4, 37Β°C, 2 CDU) and ethanol series dehydration. Importantly, distinct and reversible colour transitions were observed between acidic (pH 5) and alkaline (pH 8) environments, with up to 88 wt.% dye retention following 72-hour incubation. The fibres were successfully processed into woven dressing prototypes and demonstrated knotting ability suitable for suture applications. Overall, these wet-spun collagen fibres integrate infection-responsive capability, biodegradability, and scalable fabrication, representing a promising platform for smart wound dressings and resorbable sutures.