Possibility of hypothetical stable micro black hole production at future 100 TeV collider

We study the phenomenology of TeV-scale black holes predicted in theories with large extra dimensions, under the further assumption that they are absolutely stable. Our goal is to present an exhaustive analysis of safety of the proposed 100 TeV collider, as it was done in the case of the LHC. We consider the theories with different number of extra dimensions and identify those for which a possible accretion to macroscopic size would have timescales shorter than the lifetime of the Solar system. We calculate the cross sections of the black hole production at the proposed 100 TeV collider, the fraction of the black holes trapped inside the Earth and the resulting rate of capture inside the Earth via an improved method. We study the astrophysical consequences of stable micro black holes existence, in particular its influence on the stability of white dwarfs and neutron stars. We obtain constraints for the previously unexplored range of higher-dimensional Planck mass values. Several astrophysical scenarios of the micro black hole production, which were not considered before, are taken into account. Finally, using the astrophysical constraints we consider the implications for future 100 TeV terrestrial experiments. We exclude the possibility of the charged stable micro black holes production.Comment: 11 pages, 8 figures, accepted for publication in EPJ

Generic axion Maxwell equations: path integral approach

Using the path integral approach, we derive the low energy interactions between axions and electromagnetic field that arise in models with heavy dyons charged under a spontaneously broken global axial $U(1)$ symmetry. Hence, we obtain generic axion-Maxwell equations relevant for experimental searches. We find that the structure of the axion Maxwell equations could be significantly different compared to what is normally assumed in the literature, as the derived equations feature new axion-dependent terms including CP-violating ones. The new terms can reconcile the Peccei-Quinn solution to the strong CP problem with astrophysical axion hints, as well as give unique signatures in light-shining-through-wall and haloscope experiments. Moreover, via the latter signatures, these experiments can indirectly probe the existence of heavy dyons.Comment: Accepted for publication in Annalen der Physik; an appendix is added where we give a mathematical proof disproving the claim that the theta-term in a U(1) gauge theory generates electric charge proportional to theta for every magnetic monopole of the theory; 22 page

Photophilic hadronic axion from heavy magnetic monopoles

We propose a model for the QCD axion which is realized through a coupling of the Peccei-Quinn scalar field to magnetically charged fermions at high energies. We show that the axion of this model solves the strong CP problem and then integrate out heavy magnetic monopoles using the Schwinger proper time method. We find that the model discussed yields axion couplings to the Standard Model which are drastically different from the ones calculated within the KSVZ/DFSZ-type models, so that large part of the corresponding parameter space can be probed by various projected experiments. Moreover, the axion we introduce is consistent with the astrophysical hints suggested both by anomalous TeV-transparency of the Universe and by excessive cooling of horizontal branch stars in globular clusters. Assuming infrared Abelian dominance in QCD, we show that the leading term for the cosmic axion abundance is not changed compared to the conventional pre-inflationary QCD axion case for much of the allowed parameter space.Comment: 22 pages, 2 figure

ALGORITHM DESIGN FOR SHIP’S STEERING WITH SPECIFIED LIMITATIONS UNDER VARIOUS WEATHER CONDITIONS

The problems of developing the risk assessment methods to estimate the level of safety of the vessel under the current conditions on a planned route before staring the pilotage as well as to make the decision on the beginning or suspension of pilotage in order to increase the level of navigational safety are discussed in the paper. Moreover, the application of the research results will reduce the affect of the human factor in decision-making in tasks related to the sea-going vessel’s operation. The developed method for the quantitative assessment of navigational risks will improve the safety of ship’s pilotage. It can also be applied in the decision-making support systems for the navigator in case of collision avoidance actions. The research results presented in this paper can be used to create automatic control systems

Návrh testovacího panelu pro ochrany nízkého napětí

This thesis represents the theoretical description and practical implementation of the LV asynchronous motor protection and control solution with the usage of ABB UMC100 device – a comprehensive motor controller. The theoretical part of the diploma thesis contains the description of the most common faults happening to the motor which must be resolved, it also contains the different possible ways to control and start the motor and their advantages, as well as information about the UMC100 device itself, its elements and functions. The practical part shows the demo panel assembly for motor protection and control, its structure and parametrization, tests and measurements of the panel functions and parameters.Tato práce představuje teoretický popis a praktické provedení řešení ochrany a řízení asynchronních motorů NN s využitím zařízení ABB UMC100 – komplexního ovladače motoru. Teoretická část diplomové práce obsahuje popis nejčastějších poruch motoru, které je třeba řešit, dále obsahuje různé možné způsoby ovládání a spouštění motoru a jejich výhody a také informace o samotném zařízení UMC100 , jeho prvky a funkce. Praktická část ukazuje demo panel sestavy pro ochranu a řízení motoru, její strukturu a parametrizaci, testy a měření funkcí a parametrů panelu.410 - Katedra elektroenergetikyvýborn

Efficient Linkable Ring Signature from Vector Commitment inexplicably named Multratug

In this paper we revise the idea of our previous work ‘Lin2-Xor lemma and Log-size Linkable Threshold Ring Signature’ and introduce another lemma, called Lin2-Choice, which extends the Lin2-Xor lemma. Using an novel zero-knowledge membership proof argument defined in the Lin2-Choice lemma, we create a compact general-purpose trusted-setup-free log-size linkable threshold ring signature called EFLRSL. The signature size is 2log(n+1)+3l+1, where n is the ring size and l is the threshold. By extending the membership argument of the Lin2-Choice lemma, we create a multifunctional version of the EFLRSL signature aliased as Multratug, of size 2log(n+l+1)+7l+4. In addition to signing a message, Multratug simultaneously proves balance and allows for easy multiparty signing. We use an arbitrary vector commitment argument in the role of the pivotal building block for both versions of our signature, considering it as a black box. Only the black-boxed pivot contributes components that depend on the ring size n into the signature sizes. This makes both of EFLRSL and Multratug combinable with other proofs, with overall size reduction. All this takes place in a prime-order group without bilinear parings under the decisional Diffie-Hellman assumption in the random oracle model. Both versions of our signature are proved unforgeable w.r.t. insider corruption and existentially unforgeable under chosen message attack. They remain anonymous even for non-uniformly distributed and malformed keys, which makes it possible to use them as a log-size drop-in replacement for LSAG-based schemes

Lin2-Xor Lemma and Log-size Linkable Threshold Ring Signature

In this paper we introduce a novel method of constructing a linkable threshold ring signature without a trusted setup in a group where the decisional Diffie-Hellman problem is hard and no bilinear pairings exist. Our ring signature is logarithmic in anonymity set size and linear in signer threshold, its verification complexity is quasilinear. A range of the recently proposed setup-free logarithmic size signatures is based on the commitment-to-zero proving system by Groth and Kohlweiss or on the Bulletproofs inner-product compression method by Bünz et al. In contrast, we construct our signature from scratch using the Lin2-Xor and lemma-Lin2-Selector lemmas that we formulate and prove herein. The Lin2-Xor lemma itself provides a novel 2-round public coin OR-proof protocol, whereas the Lin2-Selector lemma generalizes it to an n-round public coin proof of membership. Consequently, we construct an n-round special honest verifier zero knowledge proof of membership and instantiate it in the form of a general-purpose setup-free linkable threshold ring signature in the random oracle model. Also, we show the signature is anonymous, has witness-extended emulation, is unforgeable and non-frameable