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We address the question of minimal requirements for the existence of quantum bound states. In particular, we demonstrate that a few-body system with zero-range momentum-independent two-body interactions is unstable against decay into clusters, if mixed-symmetry of its wave function is enforced. We claim that any theory in which the two-body scattering length is much larger than any other scale involved exhibits such instability. We exemplify this with the inability of the leading-order pionless effective field theory to describe stable states of $A>4$ nuclei. A finite interaction range is identified as a sufficient condition for a bound mixed-symmetry system. The minimal value of this range depends on the proximity of a system to unitarity, on the number of constituents, and on the particular realization of discrete scale invariance of the three-body spectrum., Comment: 15 pages, 3 figures

We review the current status of our study of $K^-$-nuclear interactions and $K^-$-nuclear quasi-bound states. The adopted $K^-$-nuclear optical potential consists of two parts -- the single-nucleon one constructed microscopically from chirally motivated $\bar{K}N$ amplitudes, and a phenomenological multi-nucleon one constrained in fits to kaonic atoms data. The inclusion of multi-nucleon absorption in our calculations of $K^{-}$ quasi-bound states in many-body systems leads to huge widths, considerably exceeding the binding energies. If this feature is confirmed the observation of such states is unlikely. Finally, a development of a new microscopical model for in-medium $K^-NN$ absorption is discussed as well., Comment: 7 pages, 9 figures, to appear in MENU2019 conference proceedings

A recent suggestion [PLB 774 (2017) 522] that purely-$\Lambda^{\ast}(1405)$ nuclei provide the absolute minimum energy in charge-neutral baryon matter for baryon-number $A\gtrsim 8$, is tested within RMF calculations. A broad range of $\Lambda^{\ast}$ interaction strengths, commensurate with $(\bar K \bar K NN)_{I=0}$ binding energy assumed to be of order 100 MeV, is scanned. It is found that the binding energy per $\Lambda^{\ast}$, $B/A$, saturates for $A\gtrsim 120$ with values of $B/A$ considerably below 100 MeV, implying that $\Lambda^{\ast}(1405)$ matter is highly unstable against strong decay to $\Lambda$ and $\Sigma$ hyperon aggregates. The central density of $\Lambda^{\ast}$ matter is found to saturate as well, at roughly twice nuclear matter density. Moreover, it is shown that the underlying very strong $\bar K N$ potentials, fitted for isospin $I=0$ to the mass and width values of $\Lambda^{\ast}(1405)$, fail to reproduce values of single-nucleon absorption fractions deduced across the periodic table from $K^-$ capture-at-rest bubble chamber experiments., Comment: v2 -- slightly added discussion, version accepted for publication in Phys. Lett. B

We studied the ${\bar p}$ interactions with the nuclear medium within the 2009 version of the Paris ${\bar N}N$ potential model. We constructed the $\bar{p}$--nucleus optical potential using the Paris $S$- and $P$-wave ${\bar p}N$ scattering amplitudes and treated their strong energy and density dependence self-consistently. We considered a phenomenological $P$-wave term as well. We calculated $\bar{p}$ binding energies and widths of the $\bar{p}$ bound in various nuclei. The $P$-wave potential has very small effect on the calculated ${\bar p}$ binding energies, however, it reduces the corresponding widths noticeably. Moreover, the $S$-wave potential based on the Paris amplitudes supplemented by a phenomenological $P$-wave term yields the ${\bar p}$ binding energies and widths in very good agreement with those obtained within the RMF model consistent with ${\bar p}$-atom data., Comment: 7 pages, 4 figures, proceedings of the EXA2017 conference, Vienna, Austria, September 11 - 15, 2017

Recent studies of $\eta$ nuclear quasibound states by the Jerusalem-Prague Collaboration are reviewed, focusing on stochastic variational method self consistent calculations of $\eta$ few-nucleon systems. These calculations suggest that a minimum value Re$\,a_{\eta N} \approx 1$ fm (0.7 fm) is needed to bind $\eta\,^3$He ($\eta\,^4$He)., Comment: presented by A. Gal at EXA2017, Vienna, Sept. 2017; written up for EPJ Web of Conferences

$K^-$ mesons offer a unique setting where mesic atoms have been studied both experimentally and theoretically, thereby placing constraints on the possible existence and properties of meson-nuclear quasibound states. Here we review progress in this field made recently by the Jerusalem--Prague Collaboration using near-threshold $K^-N$ scattering amplitudes generated in several meson--baryon coupled channels models inspired by a chiral EFT approach. Our own procedure of handling subthreshold kinematics self consistently is used to transform these free-space energy dependent amplitudes to in-medium density dependent amplitudes from which $K^-$ optical potentials are derived. To fit the world data of kaonic atoms, these single-nucleon optical potentials are augmented by multi-nucleon terms. It is found that only two of the studied models reproduce also the single-nucleon absorption fractions available from old bubble chamber experiments. These two models are then checked for possible $K^-$ nuclear quasibound states, despite realizing that $K^-$ optical potentials are not constrained by kaonic atom data at densities exceeding half nuclear-matter density. We find that when such states exist, their widths are invariably above 100 MeV, forbiddingly large to allow observation. Multi-nucleon absorption is found to be substantial in this respect. This suggests that observable strongly bound $K^-$ mesons are limited to the very light systems, such as $K^-pp$., Comment: presented by A. Gal at Hadron2017, Sept. 2017, Salamanca, Spain; prepared for Proceedings of Science

We report on self-consistent calculations of $\bar{p}$ quasi-bound states in selected nuclei performed within the relativistic mean-field (RMF) model employing $\bar{p}$ coupling constants tuned to reproduce $\bar{p}$-atom data. We confirmed considerable polarization of the nuclear core induced by the antiproton. The $\bar{p}$ annihilation was treated dynamically, taking into account the reduced phase space in the nuclear medium as well as the compressed nuclear density. The energy available for the annihilation products was evaluated self-consistently, considering additional energy shift due to particle momenta in the ${\bar p}$-nucleus system. Next, we constructed the $\bar{p}$-nucleus optical potential using scattering amplitudes related to the latest version of the Paris $\bar{N}N$ potential. We explored energy dependence of the potential and the implications for $\bar{p}$-nucleus quasi-bound states., Comment: 6 pages, 3 figures, proceedings of the LEAP2016 conference

This contribution deals with our recent study of antibaryon interactions with the nuclear medium within the relativistic mean-field approach using antibaryon coupling constants consistent with available experimental data. We performed calculations of $\bar{B}$ ($\bar{B}=\bar{p}, \bar{\Lambda}, \bar{\Sigma}, \bar{\Xi}$) bound states in selected nuclei. Due to the lack of information on the in-medium antihyperon annihilation near threshold only the $\bar{p}$ absorption was considered. It was described by the imaginary part of a phenomenological optical potential fitted to $\bar{p}$-atom data. The annihilation was treated dynamically, taking into account explicitly the reduced phase space for annihilation products in the nuclear medium, as well as the compressed nuclear density due to the antiproton. The energy available for the annihilation products was evaluated self-consistently, considering additional energy shift due to particle momenta in the ${\bar p}$-nucleus system. Corresponding $\bar{p}$ widths were significantly reduced, however, they still remain sizable. Next, the $\bar{p}$-nucleus interaction was constructed using the latest version of the Paris $\bar{N}N$ potential. Related scattering amplitudes were used to define the complex $\bar{p}$ optical potential in the nuclear medium. The resulting $\bar{p}$ $1s$ binding energies are about 10% smaller and widths about 20% larger than those obtained with the phenomenological approach., Comment: 8 pages, 6 figures, proceedings of the 26th International Nuclear Physics Conference, Adelaide, Australia, 11-16 September, 2016

An optical potential constructed using the ${\bar p}N$ scattering amplitudes derived from the 2009 version of the Paris ${\bar N}N$ potential is applied in calculations of ${\bar p}$ quasi-bound states in selected nuclei across the periodic table. A proper self-consistent procedure for treating energy dependence of the amplitudes in a nucleus appears crucial for evaluating ${\bar p}$ binding energies and widths. Particular attention is paid to the role of $P$-wave amplitudes. While the $P$-wave potential nearly does not affect calculated ${\bar p}$ binding energies, it reduces considerably the corresponding widths. The Paris $S$-wave potential supplemented by a phenomenological $P$-wave term yields in dynamical calculations ${\bar p}$ binding energies $B_{\bar p}\approx 200$ MeV and widths $\Gamma_{\bar p}\sim~200 - 230$ MeV, which is very close to the values obtained within the RMF model consistent with ${\bar p}$-atom data., Comment: 19 pages, 10 figures, 2 tables

We performed self-consistent calculations of $K^-$-nuclear quasi-bound states using a single-nucleon $K^-$ optical potential derived from chiral meson-baryon coupled-channel interaction models, supplemented by a phenomenological $K^-$ multinucleon potential introduced recently to achieve good fits to kaonic atom data [1]. Our calculations show that the effect of $K^-$ multinucleon interactions on $K^-$ widths in nuclei is decisive. The resulting widths are considerably larger than corresponding binding energies. Moreover, when the density dependence of the $K^-$-multinucleon interactions derived in the fits of kaonic atoms is extended to the nuclear interior, the only two models acceptable after imposing as additional constraint the single-nucleon fraction of $K^-$ absorption at rest do not yield any kaonic nuclear bound state in majority of considered nuclei., Comment: 14 pages, 7 figures

Temperature, the central concept of thermal physics, is one of the most frequently employed physical quantities in common practice. Even though the operative methods of the temperature measurement are described in detail in various practical instructions and textbooks, the rigorous treatment of this concept is almost lacking in the current literature. As a result, the answer to a simple question of "what the temperature is" is by no means trivial and unambiguous. There is especially an appreciable gap between the temperature as introduced in the frame of statistical theory and the only experimentally observable quantity related to this concept, phenomenological temperature. Just the logical and epistemological analysis of the present concept of phenomenological temperature is the kernel of the contribution., Comment: 17 pages

We present a simple derivation of the nuclear shielding in paramagnetic molecules, extendable to strong spin-orbit coupling cases of relevance to lanthanides and actinides, as well as encompassing contributions from excited multiplets. While our general formulation does not need electron paramagnetic resonance parameters, using them a simple and practical expression is obtained for the special case of the zero-field-split ground-state manifold, including magnetic (Zeeman and hyperfine) couplings between the sublevels. The latter method is implemented computationally and applied in the context of first-principles calculations on example Ni(II) and Co(II) complexes., Comment: This paper has been withdrawn by the author as it is incorrect. No further revisions

Correct treatment of subthreshold Kbar-N dynamics is mandatory in kaonic-atom and Kbar-nuclear bound-state calculations, as demonstrated by using in-medium chirally-based models of Kbar-N interactions. Recent studies of kaonic-atom data reveal appreciable multi-nucleon contributions. Kbar-nuclear widths larger than 50 MeV are anticipated., Comment: Invited talk by A. Gal in MESON 2014, Cracow, May-June 2014, written up for EPJ Web of Conferences, updating an earlier Conference Proceedings (arXiv:1402.3778)

The role played by subthreshold meson-baryon dynamics is demonstrated in kaonic-atom, Kbar-nuclear and eta-nuclear bound-state calculations within in-medium models of Kbar-N and eta-N interactions. New analyses of kaonic atom data reveal appreciable multi-nucleon contributions. Calculations of eta-nuclear bound states show, in particular, that the eta-N scattering length is not a useful indicator of whether or not eta mesons bind in nuclei nor of the widths anticipated for such states., Comment: invited talk at the Second International Symposium on Mesic Nuclei, Cracow, Sept.22-24 2013, matches published version

In the present contribution we analyse a simple thought process at T = 0 in an idealized heat engine having partitions made of a material with an upper frequency cut-off and bathed in zero-point (ZP) electromagnetic radiation. As a result, a possible mechanism of filling real cavities with ZP radiation based on Doppler's effect has been suggested and corresponding entropy changes are discussed., Comment: 9 pages, 1 figure

The Budd-Vannimenus theorem is modified to the surface of superconductors in the Meissner state. This identity links the surface value of the electrostatic potential to the free energy in the bulk which allows one to evaluate the observed potential without the explicit solution of the charge profile at the surface., Comment: 4 pages 1 figure

The electrostatic Bernoulli potential measured at the surface of a superconductor via Kelvin capacitive coupling is shown to be independent of the pairing mechanism. This contrasts with the Bernoulli potential in the bulk where contributions due to pairing dominate close to $T_c$., Comment: 2 pages