Higher derivative gravity and holography

In de afgelopen eeuw heeft de inzet van natuurkundigen geleid tot een theorie die drie fundamentele natuurkrachten beschrijft, de elektromagnetische kracht, de zwakke kernkracht en de sterke kernkracht. Elke poging om de vierde natuurkracht, zwaartekracht, hiermee te verenigen is tot nu toe onbevredigend geweest. Om de aard van de zwaartekracht beter te begrijpen is het holografisch principe ontwikkeld. Dit is geïnspireerd door de eigenschappen van zwarte gaten en laat een verband zien tussen de zwaartekrachttheorie en de veel beter begrepen kwantum velden theorie. Men kan zich dan afvragen of het mogelijk is om beperkingen of onbekende effecten te vinden als we buiten de bekende formulering van het holografisch principe kijken. Dit proefschrift probeert deze vraag te beantwoorden door wiskundige structuren en fysische grootheden te gebruiken als gereedschap om het principe mee te verkennen. Dit wordt gedaan in de context van een aangepaste zwaartekrachttheorie genaamd New Massive Gravity. We zien dat New Massive Gravity ons meer vrijheid geeft in deze verkenning omdat het een breder spectrum aan oplossingen biedt. Daarnaast laat het bestuderen van de fysische grootheid verstrengelingsentropy zien dat er een relatie is tussen de kwantum eigenschappen van materie en de wiskundige eigenschappen van een geometrisch object. Deze relatie kan alleen bestaan als we het holografisch principe beschouwen met een aangepaste zwaartekrachttheorie

Higher derivative gravity and holography

In de afgelopen eeuw heeft de inzet van natuurkundigen geleid tot een theorie die drie fundamentele natuurkrachten beschrijft, de elektromagnetische kracht, de zwakke kernkracht en de sterke kernkracht. Elke poging om de vierde natuurkracht, zwaartekracht, hiermee te verenigen is tot nu toe onbevredigend geweest. Om de aard van de zwaartekracht beter te begrijpen is het holografisch principe ontwikkeld. Dit is geïnspireerd door de eigenschappen van zwarte gaten en laat een verband zien tussen de zwaartekrachttheorie en de veel beter begrepen kwantum velden theorie. Men kan zich dan afvragen of het mogelijk is om beperkingen of onbekende effecten te vinden als we buiten de bekende formulering van het holografisch principe kijken. Dit proefschrift probeert deze vraag te beantwoorden door wiskundige structuren en fysische grootheden te gebruiken als gereedschap om het principe mee te verkennen. Dit wordt gedaan in de context van een aangepaste zwaartekrachttheorie genaamd New Massive Gravity. We zien dat New Massive Gravity ons meer vrijheid geeft in deze verkenning omdat het een breder spectrum aan oplossingen biedt. Daarnaast laat het bestuderen van de fysische grootheid verstrengelingsentropy zien dat er een relatie is tussen de kwantum eigenschappen van materie en de wiskundige eigenschappen van een geometrisch object. Deze relatie kan alleen bestaan als we het holografisch principe beschouwen met een aangepaste zwaartekrachttheorie

Supersymmetric Backgrounds and Black Holes in N=(1,1){\cal N}=(1,1) Cosmological New Massive Supergravity

Using an off-shell Killing spinor analysis we perform a systematic investigation of the supersymmetric background and black hole solutions of the ${\cal N}=(1,1)$ Cosmological New Massive Gravity model. The solutions with a null Killing vector are the same pp-wave solutions that one finds in the ${\cal N}=1$ model but we find new solutions with a time-like Killing vector that are absent in the ${\cal N}=1$ case. An example of such a solution is a Lifshitz spacetime. We also consider the supersymmetry properties of the so-called rotating hairy BTZ black holes and logarithmic black holes in an $AdS_3$ background. Furthermore, we show that under certain assumptions there is no supersymmetric Lifshitz black hole solution.Comment: 27 pages, v2: Typos Corrected, Version appeared in JHE

Unitarity problems in 3D gravity theories

We revisit the problem of the bulk-boundary unitarity clash in 2 + 1 dimensional gravity theories, which has been an obstacle in providing a viable dual two-dimensional conformal field theory for bulk gravity in anti-de Sitter (AdS) spacetime. Chiral gravity, which is a particular limit of cosmological topologically massive gravity (TMG), suffers from pertur- bative log-modes with negative energies inducing a non-unitary logarithmic boundary field theory. We show here that any f(R) extension of TMG does not improve the situation. We also study the perturbative modes in the metric formulation of minimal massive gravity- originally constructed in a first-order formulation-and find that the massive mode has again negative energy except in the chiral limit. We comment on this issue and also discuss a possible solution to the problem of negative energy modes. In any of these theories, the infinitesimal dangerous deformations might not be integrable to full solutions; this suggests a linearization instability of AdS spacetime in the direction of the perturbative log-modes.Comment: 15 pages, matches the Physics. Rev. D versio

Massive N=2 Supergravity in Three Dimensions

There exists two distinct off-shell ${\mathcal{N}}=2$ supergravities in three dimensions. They are also referred to as ${\mathcal{N}}=(1,1)$ and ${\mathcal{N}}=(2,0)$ supergravities, and they arise from the coupling of the Weyl multiplet to a compensating scalar or vector multiplet, respectively, followed by fixing of conformal symmetries. The ${\mathcal{N}} =(p,q)$ terminology refers to the underlying anti-de Sitter superalgebras $OSp(2,p) \oplus OSp(2,q)$ with $R$-symmetry group $SO(p) \times SO(q)$. We construct off-shell invariants of these theories up to fourth order in derivatives. As an application of these results, we determine the special combinations of the ${\mathcal{N}}=(1,1)$ invariants that admit anti-de Sitter vacuum solution about which there is a ghost-free massive spin-2 multiplet of propagating modes. We also show that the ${\mathcal{N}}=(2,0)$ invariants do not allow such possibility.Comment: 32 pages, v3: Typos Corrected, Version appeared in JHE

Food-Borne Viruses in Shellfish: Investigation on Norovirus and HAV Presence in Apulia (SE Italy)

Shellfish are an important vehicle for transmission of food-borne pathogens including norovirus (NoV) and hepatitis A virus (HAV). The risks related with consumption of shellfish are greater if these products are eaten raw or slightly cooked. As molluscs are filter-feeding organisms, they are able to concentrate pathogens dispersed in the water. Data on shellfish viral contamination are therefore useful to obtain a background information on the presence of contamination in the environment, chiefly in shellfish production areas and to generate a picture of the epidemiology of viral pathogens in local populations. From January 2013 to July 2015, 253 samples of bivalve molluscs collected in harvesting areas from a large coastal tract (860 km) of Southern Italy were screened for HAV and NoV of genogroups GI and GII, using real-time reverse transcription qualitative PCR. The RNA of HAV was not detected in any of the analyzed samples. In contrast, the RNA of NoV was identified in 14.2% of the samples with a higher prevalence of NoVs of genogroup GII (12.2%) than genogroup GI (1.6%). Upon sequence analysis of a short diagnostic region located in capsid region, the NoV strains were characterized as GII.2, GII.4 Sydney 2012, GII.6, GII.13, GI.4, and GI.6, all which were circulating in local populations in the same time span. These data confirm that consumption of mussels can expose consumers to relevant risks of infection. Also, matching between the NoV genotypes circulating in local population and detected in molluscs confirms the diffusion in the environment of NoVs

Short communication: Isolation of Shiga toxin-producing Escherichia coli in raw milk and mozzarella cheese in southern Italy

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Food-Borne Viruses in Shellfish: Investigation on Norovirus and HAV Presence in Apulia (SE Italy)

Shellfish are an important vehicle for transmission of food-borne pathogens including norovirus (NoV) and hepatitis A virus (HAV). The risks related with consumption of shellfish are greater if these products are eaten raw or slightly cooked. As molluscs are filter-feeding organisms, they are able to concentrate pathogens dispersed in the water. Data on shellfish viral contamination are therefore useful to obtain a background information on the presence of contamination in the environment, chiefly in shellfish production areas and to generate a picture of the epidemiology of viral pathogens in local populations. From January 2013 to July 2015, 253 samples of bivalve molluscs collected in harvesting areas from a large coastal tract (860 km) of Southern Italy were screened for HAV and NoV of genogroups GI and GII, using real-time reverse transcription qualitative PCR. The RNA of HAV was not detected in any of the analyzed samples. In contrast, the RNA of NoV was identified in 14.2% of the samples with a higher prevalence of NoVs of genogroup GII (12.2%) than genogroup GI (1.6%). Upon sequence analysis of a short diagnostic region located in capsid region, the NoV strains were characterized as GII.2, GII.4 Sydney 2012, GII.6, GII.13, GI.4, and GI.6, all which were circulating in local populations in the same time span. These data confirm that consumption of mussels can expose consumers to relevant risks of infection. Also, matching between the NoV genotypes circulating in local population and detected in molluscs confirms the diffusion in the environment of NoVs

First Report of Hepatitis E Virus in Shellfish in Southeast Italy

Hepatitis E virus (HEV) represents one of the principal causative agents of hepatitis globally. Among the five HEV genotypes affecting humans, genotypes 3 and 4 are zoonotic and are the main source of hepatitis E in developed countries. HEV has been detected in several foods. The present work investigated the presence of this virus in shellfish sold at retail in the Apulia region of Italy. The presence of HEV RNA was assessed by real-time RT-PCR in 225 shellfish samples collected during 2018. Overall, two (0.89%) of these samples tested positive for HEV RNA. To our knowledge, this is the first notification of the detection of HEV in mussels sold at retail in the Apulia region. These data highlight the potential role of shellfish as a vehicle for the transmission of viral pathogens