The Gravity Dual of the Ising Model

We evaluate the partition function of three dimensional theories of gravity in the quantum regime, where the AdS radius is Planck scale and the central charge is of order one. The contribution from the AdS vacuum sector can - with certain assumptions - be computed and equals the vacuum character of a minimal model CFT. The torus partition function is given by a sum over geometries which is finite and computable. For generic values of Newton's constant G and the AdS radius L the result has no Hilbert space interpretation, but in certain cases it agrees with the partition function of a known CFT. For example, the partition function of pure Einstein gravity with G=3L equals that of the Ising model, providing evidence that these theories are dual. We also present somewhat weaker evidence that the 3-state and tricritical Potts models are dual to pure higher spin theories of gravity based on SL(3) and E_6, respectively.Comment: 42 page

Higher Spin Black Holes from CFT

Higher spin gravity in three dimensions has explicit black holes solutions, carrying higher spin charge. We compute the free energy of a charged black hole from the holographic dual, a 2d CFT with extended conformal symmetry, and find exact agreement with the bulk thermodynamics. In the CFT, higher spin corrections to the free energy can be calculated at high temperature from correlation functions of W-algebra currents.Comment: 24 pages; v2 reference adde

Quantum W-symmetry in AdS_3

It has recently been argued that, classically, massless higher spin theories in AdS_3 have an enlarged W_N-symmetry as the algebra of asymptotic isometries. In this note we provide evidence that this symmetry is realised (perturbatively) in the quantum theory. We perform a one loop computation of the fluctuations for a massless spin $s$ field around a thermal AdS_3 background. The resulting determinants are evaluated using the heat kernel techniques of arXiv:0911.5085. The answer factorises holomorphically, and the contributions from the various spin $s$ fields organise themselves into vacuum characters of the W_N symmetry. For the case of the hs(1,1) theory consisting of an infinite tower of massless higher spin particles, the resulting answer can be simply expressed in terms of (two copies of) the MacMahon function.Comment: 23 pages; v2: References adde

The Uncertainty Principle in the Presence of Quantum Memory

The uncertainty principle, originally formulated by Heisenberg, dramatically illustrates the difference between classical and quantum mechanics. The principle bounds the uncertainties about the outcomes of two incompatible measurements, such as position and momentum, on a particle. It implies that one cannot predict the outcomes for both possible choices of measurement to arbitrary precision, even if information about the preparation of the particle is available in a classical memory. However, if the particle is prepared entangled with a quantum memory, a device which is likely to soon be available, it is possible to predict the outcomes for both measurement choices precisely. In this work we strengthen the uncertainty principle to incorporate this case, providing a lower bound on the uncertainties which depends on the amount of entanglement between the particle and the quantum memory. We detail the application of our result to witnessing entanglement and to quantum key distribution.Comment: 5 pages plus 12 of supplementary information. Updated to match the journal versio

Origin and Biology of Simian Immunodeficiency Virus in Wild-Living Western Gorillas

Western lowland gorillas (Gorilla gorilla gorilla) are infected with a simian immunodeficiency virus (SIVgor) that is closely related to chimpanzee and human immunodeficiency viruses (SIVcpz and HIV-1, respectively) in west central Africa. Although existing data suggest a chimpanzee origin for SIVgor, a paucity of available sequences has precluded definitive conclusions. Here, we report the molecular characterization of one partial (BQ664) and three full-length (CP684, CP2135, and CP2139) SIVgor genomes amplified from fecal RNAs of wild-living gorillas at two field sites in Cameroon. Phylogenetic analyses showed that all SIVgor strains clustered together, forming a monophyletic lineage throughout their genomes. Interestingly, the closest relatives of SIVgor were not SIVcpzPtt strains from west central African chimpanzees (Pan troglodytes troglodytes) but human viruses belonging to HIV-1 group O. In trees derived from most genomic regions, SIVgor and HIV-1 group O formed a sister clade to the SIVcpzPtt lineage. However, in a tree derived from 5' pol sequences (similar to 900 bp), SIVgor and HIV-1 group O fell within the SIVcpzPtt radiation. The latter was due to two SIVcpzPtt strains that contained mosaic pol sequences, pointing to the existence of a divergent SIVcpzPtt lineage that gave rise to SIVgor and HIV-1 group O. Gorillas appear to have acquired this lineage at least 100 to 200 years ago. To examine the biological properties of SIVgor, we synthesized a full-length provirus from fecal consensus sequences. Transfection of the resulting clone (CP2139.287) into 293T cells yielded infectious virus that replicated efficiently in both human and chimpanzee CD4(+) T cells and used CCR5 as the coreceptor for viral entry. Together, these results provide strong evidence that P. t. troglodytes apes were the source of SIVgor. These same apes may also have spawned the group O epidemic; however, the possibility that gorillas served as an intermediary host cannot be excluded

A solid state light-matter interface at the single photon level

Coherent and reversible mapping of quantum information between light and matter is an important experimental challenge in quantum information science. In particular, it is a decisive milestone for the implementation of quantum networks and quantum repeaters. So far, quantum interfaces between light and atoms have been demonstrated with atomic gases, and with single trapped atoms in cavities. Here we demonstrate the coherent and reversible mapping of a light field with less than one photon per pulse onto an ensemble of 10 millions atoms naturally trapped in a solid. This is achieved by coherently absorbing the light field in a suitably prepared solid state atomic medium. The state of the light is mapped onto collective atomic excitations on an optical transition and stored for a pre-programmed time up of to 1 mu s before being released in a well defined spatio-temporal mode as a result of a collective interference. The coherence of the process is verified by performing an interference experiment with two stored weak pulses with a variable phase relation. Visibilities of more than 95% are obtained, which demonstrates the high coherence of the mapping process at the single photon level. In addition, we show experimentally that our interface allows one to store and retrieve light fields in multiple temporal modes. Our results represent the first observation of collective enhancement at the single photon level in a solid and open the way to multimode solid state quantum memories as a promising alternative to atomic gases.Comment: 5 pages, 5 figures, version submitted on June 27 200

Prospective longitudinal study of immune checkpoint molecule (ICM) expression in immune cell subsets during curative conventional therapy of head and neck squamous cell carcinoma (HNSCC)

Programmed-death-1 (PD1) antibodies are approved for recurrent and metastatic head and neck squamous cell carcinoma. Multiple drugs targeting costimulatory and coinhibitory immune checkpoint molecules (ICM) have been discovered. However, it remains unknown how these ICM are affected by curative conventional therapy on different immune cell subsets during the course of treatment. In the prospective noninterventional clinical study titled “Immune Response Evaluation to Curative conventional Therapy” (NCT03053661), 22 patients were prospectively enrolled. Blood samples were drawn at defined time points throughout curative conventional treatment and follow-up. Immune cells (IC) from the different time points were assessed by multicolor flow cytometry. The following ICM were measured by flow cytometry: PD1, CTLA4, BTLA, CD137, CD27, GITR, OX40, LAG3 and TIM3. Dynamics of ICM expression were assessed using nonparametric paired samples tests. Significant changes were noted for PD1, BTLA and CD27 on multiple IC types during or after radiotherapy. Nonsignificant trends for increased expression of OX40 and GITR from baseline until the end of RT were observed on CD4 T cells and CD4+ CD39+ T cells. In patients with samples at recurrence of disease, a nonsignificant increase of TIM3 and LAG3 positive CD4+ CD39+ T cells was evident, accompanied by an increase of double positive cells for TIM3/LAG3. Potential future targets to be combined with RT in the conventional treatment and anti-PD1/PD-L could be BTLA agonists, or agonistic antibodies to costimulatory ICM like CD137, OX40 or GITR. The combination of cetuximab with CD27 agonistic antibodies enhancing ADCC or the targeting of TIM3/LAG3 may be another promising strategy

Supersymmetric holography on AdS3

The proposed duality between Vasiliev's supersymmetric higher spin theory on AdS3 and the 't Hooft limit of the 2d superconformal Kazama-Suzuki models is analysed in detail. In particular, we show that the partition functions of the two theories agree in the large N limit.Comment: 25 pages, 3 figures, improved fig.

Minimal Model Holography

We review the duality relating 2d W_N minimal model CFTs, in a large N 't Hooft like limit, to higher spin gravitational theories on AdS_3.Comment: 54 pages, 1 figure; Contribution to J. Phys. A special volume on "Higher Spin Theories and AdS/CFT" edited by M. R. Gaberdiel and M. Vasiliev. v2. minor change

A rev1–vpu polymorphism unique to HIV-1 subtype A and C strains impairs envelope glycoprotein expression from rev–vpu–env cassettes and reduces virion infectivity in pseudotyping assays

Functional studies of HIV-1 envelope glycoproteins (Envs) commonly include the generation of pseudoviruses, which are produced by co-transfection of rev-vpu-env cassettes with an env-deficient provirus. Here, we describe six Env constructs from transmitted/founder HIV-1 that were defective in the pseudotyping assay, although two produced infectious virions when expressed from their cognate proviruses. All of these constructs exhibited an unusual gene arrangement in which the first exon of rev (rev1) and vpu were in the same reading frame without an intervening stop codon. Disruption of the rev1-vpu fusion gene by frameshift mutation, stop codon, or abrogation of the rev initiation codon restored pseudovirion infectivity. Introduction of the fusion gene into wildtype Env cassettes severely compromised their function. The defect was not due to altered env and rev transcription or a dominant negative effect of the expressed fusion protein, but seemed to be caused by inefficient translation at the env initiation codon. Although the rev1-vpu polymorphism affects Env expression only in vitro, it can cause problems in studies requiring Env complementation, such as analyses of co-receptor usage and neutralization properties, since 3% of subtype A, 20% of subtype C and 5% of CRF01_A/E viruses encode the fusion gene. A solution is to eliminate the rev initiation codon when amplifying rev-vpu-env cassettes since this increases Env expression irrespective of the presence of the polymorphism