Surveying structural complexity in quantum many-body systems

Quantum many-body systems exhibit a rich and diverse range of exotic behaviours, owing to their underlying non-classical structure. These systems present a deep structure beyond those that can be captured by measures of correlation and entanglement alone. Using tools from complexity science, we characterise such structure. We investigate the structural complexities that can be found within the patterns that manifest from the observational data of these systems. In particular, using two prototypical quantum many-body systems as test cases - the one-dimensional quantum Ising and Bose-Hubbard models - we explore how different information-theoretic measures of complexity are able to identify different features of such patterns. This work furthers the understanding of fully-quantum notions of structure and complexity in quantum systems and dynamics.Comment: 9 pages, 5 figure

Ferrocene-1-carbaldehyde 4-ethyl­thio­semi­carbazone

The asymmetric unit of title compound, [Fe(C5H5)(C9H12N3S)], contains two crystallographically independent mol­ecules, A and B. The two cyclo­penta­dienyl (Cp) rings are parallel to each other in both mol­ecules, forming dihedral angles of 2.3 (3) and 1.0 (3)°, respectively, and adopt an eclipsed conformation. The mean plane of the semicarbazone group is twisted slightly away from the attached Cp ring in both mol­ecules, the dihedral angles between the mean plane and the Cp ring being 15.3 (2) and 10.8 (2)°. The ethyl group in mol­ecule A is coplanar with the mean plane of the semicarbazone group [C—N—C—C torsion angle = −175.2 (4)°], whereas it is nearly perpendicular in mol­ecule B [C—N—C—C torsion angle = 84.8 (6)°]. In the crystal structure, inter­molecular N—H⋯S hydrogen bonds link the mol­ecules into dimers. These dimers are further linked into chains via inter­molecular C—H⋯S hydrogen bonds. The crystal studied was a non-merohedral twin with a refined ratio of the twin components of 0.265 (2):0.735 (2)

6-Chloro-3-[5-(3-meth­oxy-8-methyl-4-quinol­yl)-1-phenyl-4,5-dihydro-1H-pyrazol-3-yl]-2-methyl-4-phenyl­quinoline

In the title compound, C36H29ClN4O, the dihydro­pyrazole ring adopts an envelope conformation. The two quinoline ring systems (r.m.s. deviations = 0.029 and 0.018 Å) are oriented at a dihedral angle of 71.43 (4)°. One of the quinoline rings makes a dihedral angle of 65.40 (7)° with the phenyl substituent. In the crystal, mol­ecules are linked into chains along the b axis by inter­molecular C—H⋯N hydrogen bonds. In addition, C—H⋯π and π–π [centroid–centroid distance = 3.7325 (8) Å] inter­actions are observed

Bis(1-ferrocenylmethyl­idene-4-phenyl­thiosemicarbazidato-κ2 N 1,S)zinc(II) monohydrate

In the title compound, [Fe2Zn(C5H5)2(C13H11N3S)2]·H2O, the ZnII ion is in a distorted tetra­hedral geometry being coordinated by two thio­semicarbazone ligands via N and S atoms. One of the Cp rings is disordered over two positions with occupancies of 0.55 and 0.45. The dihedral angle between the substituted Cp rings is 56.1 (5)° and the two phenyl rings are orientated at a dihedral angle of 41.7 (4)°. In the crystal structure, inter­molecular O—H⋯S, N—H⋯O and C—H⋯N hydrogen bonds link the mol­ecules into chains along the b axis. The structure is further consolidated by O—H⋯π inter­actions

4,5,6,7,8,9-Hexahydro-2H-cyclo­octa[c]pyrazol-1-ium-3-olate

The title compound, C9H14N2O, exists in the zwitterionic form in the crystal. The cyclo­octane ring adopts a twisted boat-chair conformation. In the crystal, inter­molecular N—H⋯O hydrogen bonds link the mol­ecules into sheets lying parallel to bc. The structure is also stabilized by π–π inter­actions, with a centroid-to-centroid distance of 3.5684 (8) Å

Two-gap and paramagnetic pair-breaking effects on upper critical field of SmFeAsO0.85_{0.85} and SmFeAsO0.8_{0.8}F0.2_{0.2} single crystals

We investigated the temperature dependence of the upper critical field [$H_{c2}(T)$] of fluorine-free SmFeAsO$_{0.85}$ and fluorine-doped SmFeAsO$_{0.8}$F$_{0.2}$ single crystals by measuring the resistive transition in low static magnetic fields and in pulsed fields up to 60 T. Both crystals show that $H_{c2}(T)$'s along the c axis [$H_{c2}^c(T)$] and in an $ab$-planar direction [$H_{c2}^{ab}(T)$] exhibit a linear and a sublinear increase, respectively, with decreasing temperature below the superconducting transition. $H_{c2}(T)$'s in both directions deviate from the conventional one-gap Werthamer-Helfand-Hohenberg theoretical prediction at low temperatures. A two-gap nature and the paramagnetic pair-breaking effect are shown to be responsible for the temperature-dependent behavior of $H_{c2}^c$ and $H_{c2}^{ab}$, respectively.Comment: 21 pages, 8 figure

Prevalence of macropod progressive periodontal disease ("lumpy jaw") in wild western grey kangaroos (Macropus fuliginosus)

Macropod Progressive Periodontal Disease (MPPD), colloquially referred to as “lumpy jaw”, is a commonly observed disease in captive macropods. However, the prevalence of this disease in the wild is largely unknown. A systematic study of MPPD in wild macropods would provide an indication of the endemic presence of this disease in wild populations, and could assist those managing disease in captive populations, by highlighting potential risk factors for disease development. Utilising kangaroos culled as part of a population management program, this study used visual observation and computer tomography (CT) of skulls to investigate the prevalence of MPPD in wild western grey kangaroos (Macropus fuliginosus) from the Perth metropolitan region, Western Australia. The sample suitable for visual and CT analysis comprised 121 specimens, 71 (58.7%) male and 50 (41.3%) female, with the mean age for all 121 specimens being 4.5 years (±2.63 SD). No evidence of MPPD was detected in any of the specimens examined. Overabundance may not be associated with the development of MPPD, as previously considered, and age-related factors should not be eliminated. This results may reflect low susceptibility to MPPD in western grey kangaroos, given low prevalence is reported in this species in captive populations. Further investigation into species-specificity is recommended, and should include samples with soft tissue to improve sensitivity of disease detection. Surveillance of MPPD in wild populations of macropods helps to improve our understanding of the biological significance, development and potential spread of this disease. Notably, this information may assist in the management of MPPD in captive populations, and may have a positive impact on both the welfare and conservation of macropods in captivity

Ferrocene-1-carbaldehyde thio­semi­carbazone

The asymmetric unit of the title compound, [Fe(C5H5)(C7H8N3S)], consists of two crystallographically independent mol­ecules, A and B. The cyclo­penta­dienyl (Cp) rings in both mol­ecules adopt an eclipsed conformation and are parallel to each other, forming dihedral angles of 2.5 (3) and 1.1 (3)°, respectively. The mean plane of the semicarbazone group is coplanar with the attached Cp ring in mol­ecule A, whereas it is twisted away in mol­ecule B. In the crystal structure, inter­molecular N—H⋯S hydrogen bonds link the mol­ecules into two-dimensional planes parallel to the ab plane. The structure is further consolidated by C—H⋯π inter­actions