@article{588, abstract = {Quantum metrology uses quantum entanglement - correlations in the properties of microscopic systems - to improve the statistical precision of physical measurements. When measuring a signal, such as the phase shift of a light beam or an atomic state, a prominent limitation to achievable precision arises from the noise associated with the counting of uncorrelated probe particles. This noise, commonly referred to as shot noise or projection noise, gives rise to the standard quantum limit (SQL) to phase resolution. However, it can be mitigated down to the fundamental Heisenberg limit by entangling the probe particles. Despite considerable experimental progress in a variety of physical systems, a question that persists is whether these methods can achieve performance levels that compare favourably with optimized conventional (non-entangled) systems. Here we demonstrate an approach that achieves unprecedented levels of metrological improvement using half a million 87Rb atoms in their 'clock' states. The ensemble is 20.1 ± 0.3 decibels (100-fold) spin-squeezed via an optical-cavity-based measurement. We directly resolve small microwave-induced rotations 18.5 ± 0.3 decibels (70-fold) beyond the SQL. The single-shot phase resolution of 147 microradians achieved by the apparatus is better than that achieved by the best engineered cold atom sensors despite lower atom numbers. We infer entanglement of more than 680 ± 35 particles in the atomic ensemble. Applications include atomic clocks, inertial sensors, and fundamental physics experiments such as tests of general relativity or searches for electron electric dipole moment. To this end, we demonstrate an atomic clock measurement with a quantum enhancement of 10.5 ± 0.3 decibels (11-fold), limited by the phase noise of our microwave source.}, author = {Onur Hosten and Engelsen, Nils J and Krishnakumar, Rajiv and Kasevich, Mark A}, journal = {Nature}, number = {7587}, pages = {505 -- 508}, publisher = {Nature Publishing Group}, title = {{Measurement noise 100 times lower than the quantum-projection limit using entangled atoms}}, doi = {10.1038/nature16176}, volume = {529}, year = {2016}, } @inproceedings{592, abstract = {We create up to 20 dB spin-squeezed states of atomic ensembles using an optical cavity-based measurement. The prepared states are suitable for atomic sensors that require free space release of the atoms.}, author = {Engelsen, Nils and Hosten, Onur and Krishnakumar, Rajiv and Kasevich, Mark}, location = {San Jose, CA, United States}, publisher = {IEEE}, title = {{Engineering spin squeezed states for quantum-enhanced atom interferometry}}, year = {2016}, } @article{602, abstract = {RNA polymerase (Pol) II produces messenger RNA during transcription of protein-coding genes in all eukaryotic cells. The Pol II structure is known at high resolution from X-ray crystallography for two yeast species1-3. Structural studies of mammalian Pol II, however, remain limited to low-resolution electron microscopy analysis of human Pol II and its complexes with various proteins4-10. Here we report the 3.4 Å resolution cryo-electron microscopy structure of mammalian Pol II in the form of a transcribing complex comprising DNA template and RNA transcript. We use bovine Pol II, which is identical to the human enzyme except for seven amino-acid residues. The obtained atomic model closely resembles its yeast counterpart, but also reveals unknown features. Binding of nucleic acids to the polymerase involves 'induced fit' of the mobile Pol II clamp and active centre region. DNA downstream of the transcription bubble contacts a conserved 'TPSA motif' in the jaw domain of the Pol II subunit RPB5, an interaction that is apparently already established during transcription initiation7. Upstream DNA emanates from the active centre cleft at an angle of approximately 105° with respect to downstream DNA. This position of upstream DNA allows for binding of the general transcription elongation factor DSIF (SPT4-SPT5) that we localize over the active centre cleft in a conserved position on the clamp domain of Pol II. Our results define the structure of mammalian Pol II in its functional state, indicate that previous crystallographic analysis of yeast Pol II is relevant for understanding gene transcription in all eukaryotes, and provide a starting point for a mechanistic analysis of human transcription.}, author = {Bernecky, Carrie A and Herzog, Franz and Baumeister, Wolfgang and Plitzko, Jürgen and Cramer, Patrick}, journal = {Nature}, number = {7587}, pages = {551 -- 554}, publisher = {Nature Publishing Group}, title = {{Structure of transcribing mammalian RNA polymerase II}}, doi = {10.1038/nature16482}, volume = {529}, year = {2016}, } @article{6732, abstract = {Consider the transmission of a polar code of block length N and rate R over a binary memoryless symmetric channel W and let P e be the block error probability under successive cancellation decoding. In this paper, we develop new bounds that characterize the relationship of the parameters R, N, P e , and the quality of the channel W quantified by its capacity I(W) and its Bhattacharyya parameter Z(W). In previous work, two main regimes were studied. In the error exponent regime, the channel W and the rate R <; I(W) are fixed, and it was proved that the error probability Pe scales roughly as 2 -√N . In the scaling exponent approach, the channel W and the error probability Pe are fixed and it was proved that the gap to capacity I(W) - R scales as N -1/μ . Here, μ is called scaling exponent and this scaling exponent depends on the channel W. A heuristic computation for the binary erasure channel (BEC) gives μ = 3.627 and it was shown that, for any channel W, 3.579 ≤ μ ≤ 5.702. Our contributions are as follows. First, we provide the tighter upper bound μ <;≤ 4.714 valid for any W. With the same technique, we obtain the upper bound μ ≤ 3.639 for the case of the BEC; this upper bound approaches very closely the heuristically derived value for the scaling exponent of the erasure channel. Second, we develop a trade-off between the gap to capacity I(W)- R and the error probability Pe as the functions of the block length N. In other words, we neither fix the gap to capacity (error exponent regime) nor the error probability (scaling exponent regime), but we do consider a moderate deviations regime in which we study how fast both quantities, as the functions of the block length N, simultaneously go to 0. Third, we prove that polar codes are not affected by error floors. To do so, we fix a polar code of block length N and rate R. Then, we vary the channel W and study the impact of this variation on the error probability. We show that the error probability Pe scales as the Bhattacharyya parameter Z(W) raised to a power that scales roughly like VN. This agrees with the scaling in the error exponent regime.}, author = {Mondelli, Marco and Hassani, S. Hamed and Urbanke, Rudiger L.}, issn = {1557-9654}, journal = {IEEE Transactions on Information Theory}, number = {12}, pages = {6698--6712}, publisher = {IEEE}, title = {{Unified scaling of polar codes: Error exponent, scaling exponent, moderate deviations, and error floors}}, doi = {10.1109/tit.2016.2616117}, volume = {62}, year = {2016}, } @inproceedings{6733, abstract = {The question whether RM codes are capacity-achieving is a long-standing open problem in coding theory that was recently answered in the affirmative for transmission over erasure channels [1], [2]. Remarkably, the proof does not rely on specific properties of RM codes, apart from their symmetry. Indeed, the main technical result consists in showing that any sequence of linear codes, with doubly-transitive permutation groups, achieves capacity on the memoryless erasure channel under bit-MAP decoding. Thus, a natural question is what happens under block-MAP decoding. In [1], [2], by exploiting further symmetries of the code, the bit-MAP threshold was shown to be sharp enough so that the block erasure probability also converges to 0. However, this technique relies heavily on the fact that the transmission is over an erasure channel. We present an alternative approach to strengthen results regarding the bit-MAP threshold to block-MAP thresholds. This approach is based on a careful analysis of the weight distribution of RM codes. In particular, the flavor of the main result is the following: assume that the bit-MAP error probability decays as N -δ , for some δ > 0. Then, the block-MAP error probability also converges to 0. This technique applies to transmission over any binary memoryless symmetric channel. Thus, it can be thought of as a first step in extending the proof that RM codes are capacity-achieving to the general case.}, author = {Kudekar, Shrinivas and Kumar, Santhosh and Mondelli, Marco and Pfister, Henry D. and Urbankez, Rudiger}, booktitle = {2016 IEEE International Symposium on Information Theory }, location = {Barcelona, Spain}, pages = {1755--1759}, publisher = {IEEE}, title = {{Comparing the bit-MAP and block-MAP decoding thresholds of Reed-Muller codes on BMS channels}}, doi = {10.1109/isit.2016.7541600}, year = {2016}, } @inproceedings{6770, abstract = {We describe a new method to compare the bit-MAP and block-MAP decoding thresholds of Reed-Muller (RM) codes for transmission over a binary memoryless symmetric channel. The question whether RM codes are capacity-achieving is a long-standing open problem in coding theory and it has recently been answered in the affirmative for transmission over erasure channels. Remarkably, the proof does not rely on specific properties of RM codes, apart from their symmetry. Indeed, the main technical result consists in showing that any sequence of linear codes, with doubly-transitive permutation groups, achieves capacity on the memoryless erasure channel under bit-MAP decoding. A natural question is what happens under block-MAP decoding. If the minimum distance of the code family is close to linear (e.g., of order N/ log(N)), then one can combine an upper bound on the bit-MAP error probability with a lower bound on the minimum distance to show that the code family is also capacity-achieving under block-MAP decoding. This strategy is successful for BCH codes. Unfortunately, the minimum distance of RM codes scales only as √N, which does not suffice to obtain the desired result. Then, one can exploit further symmetries of RM codes to show that the bit-MAP threshold is sharp enough so that the block erasure probability also tends to 0. However, this technique relies heavily on the fact that the transmission is over an erasure channel. We present an alternative approach to strengthen results regarding the bit-MAP threshold to block-MAP thresholds. This approach is based on a careful analysis of the weight distribution of RM codes. In particular, the flavor of the main result is the following: assume that the bit-MAP error probability decays as N−δ, for some δ > 0. Then, the block-MAP error probability also converges to 0. This technique applies to the transmission over any binary memoryless symmetric channel. Thus, it can be thought of as a first step in extending the proof that RM codes are capacity-achieving to the general case.}, author = {Mondelli, Marco and Kudekar, Shrinivas and Kumar, Santosh and Pfister, Henry D. and Şaşoğlu, Eren and Urbanke, Rüdiger}, booktitle = {24th International Zurich Seminar on Communications}, location = {Zurich, Switzerland}, pages = {50}, publisher = {ETH Zürich}, title = {{Reed-Muller codes: Thresholds and weight distribution}}, doi = {10.3929/ETHZ-A-010646484}, year = {2016}, } @article{7068, abstract = {Electrons in materials with linear dispersion behave as massless Weyl- or Dirac-quasiparticles, and continue to intrigue due to their close resemblance to elusive ultra-relativistic particles as well as their potential for future electronics. Yet the experimental signatures of Weyl-fermions are often subtle and indirect, in particular if they coexist with conventional, massive quasiparticles. Here we show a pronounced anomaly in the magnetic torque of the Weyl semimetal NbAs upon entering the quantum limit state in high magnetic fields. The torque changes sign in the quantum limit, signalling a reversal of the magnetic anisotropy that can be directly attributed to the topological nature of the Weyl electrons. Our results establish that anomalous quantum limit torque measurements provide a direct experimental method to identify and distinguish Weyl and Dirac systems.}, author = {Moll, Philip J. W. and Potter, Andrew C. and Nair, Nityan L. and Ramshaw, B. J. and Modic, Kimberly A and Riggs, Scott and Zeng, Bin and Ghimire, Nirmal J. and Bauer, Eric D. and Kealhofer, Robert and Ronning, Filip and Analytis, James G.}, issn = {2041-1723}, journal = {Nature Communications}, publisher = {Springer Nature}, title = {{Magnetic torque anomaly in the quantum limit of Weyl semimetals}}, doi = {10.1038/ncomms12492}, volume = {7}, year = {2016}, } @article{7069, abstract = {The observation of a reconstructed Fermi surface via quantum oscillations in hole-doped cuprates opened a path towards identifying broken symmetry states in the pseudogap regime. However, such an identification has remained inconclusive due to the multi-frequency quantum oscillation spectra and complications accounting for bilayer effects in most studies. We overcome these impediments with high-resolution measurements on the structurally simpler cuprate HgBa2CuO4+δ (Hg1201), which features one CuO2 plane per primitive unit cell. We find only a single oscillatory component with no signatures of magnetic breakdown tunnelling to additional orbits. Therefore, the Fermi surface comprises a single quasi-two-dimensional pocket. Quantitative modelling of these results indicates that a biaxial charge density wave within each CuO2 plane is responsible for the reconstruction and rules out criss-crossed charge stripes between layers as a viable alternative in Hg1201. Lastly, we determine that the characteristic gap between reconstructed pockets is a significant fraction of the pseudogap energy.}, author = {Chan, M. K. and Harrison, N. and McDonald, R. D. and Ramshaw, B. J. and Modic, Kimberly A and Barišić, N. and Greven, M.}, issn = {2041-1723}, journal = {Nature Communications}, publisher = {Springer Nature}, title = {{Single reconstructed Fermi surface pocket in an underdoped single-layer cuprate superconductor}}, doi = {10.1038/ncomms12244}, volume = {7}, year = {2016}, } @article{7141, author = {Rolando, Chiara and Erni, Andrea and Grison, Alice and Beattie, Robert J and Engler, Anna and Gokhale, Paul J. and Milo, Marta and Wegleiter, Thomas and Jessberger, Sebastian and Taylor, Verdon}, issn = {1934-5909}, journal = {Cell Stem Cell}, number = {5}, pages = {653--662}, publisher = {Elsevier}, title = {{Multipotency of adult hippocampal NSCs in vivo is restricted by Drosha/NFIB}}, doi = {10.1016/j.stem.2016.07.003}, volume = {19}, year = {2016}, } @article{7279, abstract = {Kinetics of electrochemical reactions are several orders of magnitude slower in solids than in liquids as a result of the much lower ion diffusivity. Yet, the solid state maximizes the density of redox species, which is at least two orders of magnitude lower in liquids because of solubility limitations. With regard to electrochemical energy storage devices, this leads to high-energy batteries with limited power and high-power supercapacitors with a well-known energy deficiency. For such devices the ideal system should endow the liquid state with a density of redox species close to the solid state. Here we report an approach based on biredox ionic liquids to achieve bulk-like redox density at liquid-like fast kinetics. The cation and anion of these biredox ionic liquids bear moieties that undergo very fast reversible redox reactions. As a first demonstration of their potential for high-capacity/high-rate charge storage, we used them in redox supercapacitors. These ionic liquids are able to decouple charge storage from an ion-accessible electrode surface, by storing significant charge in the pores of the electrodes, to minimize self-discharge and leakage current as a result of retaining the redox species in the pores, and to raise working voltage due to their wide electrochemical window.}, author = {Mourad, Eléonore and Coustan, Laura and Lannelongue, Pierre and Zigah, Dodzi and Mehdi, Ahmad and Vioux, André and Freunberger, Stefan Alexander and Favier, Frédéric and Fontaine, Olivier}, issn = {1476-1122}, journal = {Nature Materials}, number = {4}, pages = {446--453}, publisher = {Springer Nature}, title = {{Biredox ionic liquids with solid-like redox density in the liquid state for high-energy supercapacitors}}, doi = {10.1038/nmat4808}, volume = {16}, year = {2016}, } @article{7293, abstract = {If proton exchange membrane fuel cells (PEMFC) are ever to succeed in sustainable energy landscape as a potential zero emission technology, it is inevitable to reduce electricity production cost associated mainly with its MEAs, cell hardware and gas storage units. We demonstrate a diverse strategy for achieving this target with a concomitant amplification of its specific energy and power, by rolling a thin graphene oxide (GO) based MEA alone into a tubular and air breathing architecture with internal fuel storage. The unique properties of GO being a barrier for molecular fuels and proton conducting to construct a GO based cylindrical MEA. This makes the tubular PEMFC ∼75 times lighter, featuring ∼37 and ∼92 times respectively, the power and energy per overall weight, making it a potential candidate for portable applications. The intrinsic electrochemical kinetics at the three-phase boundary are somewhat affected by the bending of the MEA, albeit at overall reduction in power production cost.}, author = {Thimmappa, Ravikumar and Chattanahalli Devendrachari, Mruthyunjayachari and Shafi, Shahid and Freunberger, Stefan Alexander and Ottakam Thotiyl, Musthafa}, issn = {0360-3199}, journal = {International Journal of Hydrogen Energy}, number = {47}, pages = {22305--22315}, publisher = {Elsevier}, title = {{Proton conducting hollow graphene oxide cylinder as molecular fuel barrier for tubular H2-air fuel cell}}, doi = {10.1016/j.ijhydene.2016.08.057}, volume = {41}, year = {2016}, } @article{7294, abstract = {Mesoporous nanocrystalline TiO2 and TiO2–V2O5 microspheres were prepared by non-hydrolytic sol–gel from TiCl4, VOCl3, and iPr2O at 110 °C without any solvent or additives. The samples were characterized by elemental analysis, X-ray diffraction, Raman spectroscopy, scanning electron microscopy, nitrogen physisorption, and impedance measurements. At low vanadium loadings, only TiO2 anatase was detected, and V2O5 scherbinaite was also detected at high vanadium loadings. The texture of the samples depended on the V loading, but all the samples appeared built of primary nanoparticles (≈10–20 nm in size) that aggregate to form mesoporous micron-sized spheres. The lithium insertion properties of these materials were evaluated by galvanostatic measurements taken using coin-type cells, in view of their application as electrode for rechargeable Li-ion batteries. The mesoporous TiO2 microspheres showed good performances, with a specific reversible capacity of 145 and 128 mAh g−1 at C/2 and C, respectively (C = 335.6 mA g−1), good coulombic efficiency, and a moderate capacity fade (6 %) from the 2nd to the 20th cycle at C/20. Although the addition of V effectively increased the electronic conductivity of the powders, the specific reversible capacity and cycling performances of the TiO2–V2O5 samples were only minimally improved for a 5 at% V loading and were lower at higher V loading.}, author = {Escamilla-Pérez, A. M. and Louvain, N. and Kaschowitz, M. and Freunberger, Stefan Alexander and Fontaine, O. and Boury, B. and Brun, N. and Mutin, P. H.}, issn = {0928-0707}, journal = {Journal of Sol-Gel Science and Technology}, number = {2}, pages = {270--278}, publisher = {Springer Nature}, title = {{Lithium insertion properties of mesoporous nanocrystalline TiO2 and TiO2–V2O5 microspheres prepared by non-hydrolytic sol–gel}}, doi = {10.1007/s10971-016-4037-9}, volume = {79}, year = {2016}, } @article{7295, abstract = {Redox ionic liquids consisting of ions bearing redox moieties are receiving increasing interest in electrochemical applications, as they associate electroactive properties with the classical properties of ionic liquids. Here, biredox ionic liquid electrolytes are described in which both anion and cation are functionalized with anthraquinone and 2,2,6,6-tetramethylpiperidinyl-1-oxyl (TEMPO) groups, respectively. In-depth investigations based on crossed experimental and theoretical studies were carried out to elucidate how the bulkiness of ions bearing a redox moiety impacted electron and mass transfers, and accordingly the efficiency of electrochemical devices. The values of solvated radii of different redox ions, as well as the related kinetic constants, were extracted from cyclic voltammetry experiments. Reformulating the basic relations of electron transfer theory (based on Marcus-Hush theory) evidenced that in such redox species, with an unsymmetrical located redox centre, the electron transfer was not governed by the overall size of the solvated redox species, but rather by the radius of the redox active subunit, which takes preferential orientation towards the surface, thus allowing higher kinetic constants than what classical theory would predict. This vision opens ample opportunities for biredox ILs as electrolytes in electrochemical devices.}, author = {Mourad, Eléonore and Coustan, Laura and Freunberger, Stefan Alexander and Mehdi, Ahmad and Vioux, André and Favier, Frédérique and Fontaine, Olivier}, issn = {0013-4686}, journal = {Electrochimica Acta}, number = {7}, pages = {513--523}, publisher = {Elsevier}, title = {{Biredox ionic liquids: Electrochemical investigation and impact of ion size on electron transfer}}, doi = {10.1016/j.electacta.2016.02.211}, volume = {206}, year = {2016}, } @article{7296, abstract = {Within the scope of developing a multi-physical model describing battery behavior during and after the mechanical load (accelerations, intrusions) of a vehicle’s high voltage battery, an internal short circuit model is of deep interest for a virtual hazard assessment. The internal short resistance and the size of the affected area must be known as a minimum for determining the released heat and, in consequence, the temperatures. The internal short resistance of purpose-built dummy pouch cells, filled with electrolyte-like solvent without conductive salt, has thus been measured in a given short area under various compressive loads. The resistances for different short scenarios obtained are analyzed and described in a mathematical form. Short circuit experiments with dummy cells using an external power source have also been carried out. This set-up allows the measurement of the temperature evolution at a known current and a determination of the actual short resistance. The post-mortem analysis of the samples shows a correlation between the maximum temperatures, released short heat and the separator melt diameter.}, author = {Volck, Theo and Sinz, Wolfgang and Gstrein, Gregor and Breitfuss, Christoph and Heindl, Simon and Steffan, Hermann and Freunberger, Stefan Alexander and Wilkening, Martin and Uitz, Marlena and Fink, Clemens and Geier, Alexander}, issn = {2313-0105}, journal = {Batteries}, number = {2}, publisher = {MDPI AG}, title = {{Method for determination of the internal short resistance and heat evolution at different mechanical loads of a Lithium ion battery cell based on dummy pouch cells}}, doi = {10.3390/batteries2020008}, volume = {2}, year = {2016}, } @article{7297, abstract = {Redox mediators facilitate the oxidation of the highly insulating discharge product in metal–oxygen batteries during recharge and offer opportunities to achieve high reversible capacities. Now a design principle for selecting redox mediators that can recharge the batteries more efficiently is suggested.}, author = {Freunberger, Stefan Alexander}, issn = {2058-7546}, journal = {Nature Energy}, number = {6}, publisher = {Springer Nature}, title = {{Batteries: Charging ahead rationally}}, doi = {10.1038/nenergy.2016.74}, volume = {1}, year = {2016}, } @article{7298, abstract = {Lithium-ion batteries are in widespread use in electric vehicles and hybrid vehicles. Besides features like energy density, cost, lifetime, and recyclability the safety of a battery system is of prime importance. The separator material impacts all these properties and requires therefore an informed selection. The interplay between the mechanical and electrochemical properties as key selection criteria is investigated. Mechanical properties were investigated using tensile and puncture penetration tests at abuse relevant conditions. To investigate the electrochemical performance in terms of effective conductivity a method based on impedance spectroscopy was introduced. This methodology is applied to evaluate ten commercial separators which allows for a trade-off analysis of mechanical versus electrochemical performance. Based on the results, and in combination with other factors, this offers an effective approach to select suitable separators for automotive applications.}, author = {Plaimer, Martin and Breitfuß, Christoph and Sinz, Wolfgang and Heindl, Simon F. and Ellersdorfer, Christian and Steffan, Hermann and Wilkening, Martin and Hennige, Volker and Tatschl, Reinhard and Geier, Alexander and Schramm, Christian and Freunberger, Stefan Alexander}, issn = {0378-7753}, journal = {Journal of Power Sources}, number = {2}, pages = {702--710}, publisher = {Elsevier}, title = {{Evaluating the trade-off between mechanical and electrochemical performance of separators for lithium-ion batteries: Methodology and application}}, doi = {10.1016/j.jpowsour.2015.12.047}, volume = {306}, year = {2016}, } @article{7599, abstract = {Normal leaf margin development is important for leaf morphogenesis and contributes to diverse leaf shapes in higher plants. We here show the crucial roles of an atypical type II phosphatidylinositol 4-kinase, PI4Kγ5, in Arabidopsis leaf margin development. PI4Kγ5 presents a dynamics expression pattern along with leaf development and a T-DNA mutant lacking PI4Kγ5, pi4kγ5–1, presents serrated leaves, which is resulted from the accelerated cell division and increased auxin concentration at serration tips. Studies revealed that PI4Kγ5 interacts with and phosphorylates a membrane-bound NAC transcription factor, ANAC078. Previous studies demonstrated that membrane-bound transcription factors regulate gene transcription by undergoing proteolytic process to translocate into nucleus, and ANAC078 undergoes proteolysis by cleaving off the transmembrane region and carboxyl terminal. Western blot analysis indeed showed that ANAC078 deleting of carboxyl terminal is significantly reduced in pi4kγ5–1, indicating that PI4Kγ5 is important for the cleavage of ANAC078. This is consistent with the subcellular localization observation showing that fluorescence by GFP-ANAC078 is detected at plasma membrane but not nucleus in pi4kγ5–1 mutant and that expression of ANAC078 deleting of carboxyl terminal, driven by PI4Kγ5 promoter, could rescue the leaf serration defects of pi4kγ5–1. Further analysis showed that ANAC078 suppresses the auxin synthesis by directly binding and regulating the expression of auxin synthesis-related genes. These results indicate that PI4Kγ5 interacts with ANAC078 to negatively regulate auxin synthesis and hence influences cell proliferation and leaf development, providing informative clues for the regulation of in situ auxin synthesis and cell division, as well as the cleavage and functional mechanism of membrane-bound transcription factors.}, author = {Tang, Yong and Zhao, Chun-Yan and Tan, Shutang and Xue, Hong-Wei}, issn = {1553-7404}, journal = {PLOS Genetics}, number = {8}, publisher = {Public Library of Science}, title = {{Arabidopsis type II phosphatidylinositol 4-kinase PI4Kγ5 regulates auxin biosynthesis and leaf margin development through interacting with membrane-bound transcription factor ANAC078}}, doi = {10.1371/journal.pgen.1006252}, volume = {12}, year = {2016}, } @article{983, abstract = {The half-filled Landau level is expected to be approximately particle-hole symmetric, which requires an extension of the Halperin-Lee-Read (HLR) theory of the compressible state observed at this filling. Recent work indicates that, when particle-hole symmetry is preserved, the composite fermions experience a quantized π-Berry phase upon winding around the composite Fermi surface, analogous to Dirac fermions at the surface of a 3D topological insulator. In contrast, the effective low-energy theory of the composite fermion liquid originally proposed by HLR lacks particle-hole symmetry and has vanishing Berry phase. In this paper, we explain how thermoelectric transport measurements can be used to test the Dirac nature of the composite fermions by quantitatively extracting this Berry phase. First, we point out that longitudinal thermopower (Seebeck effect) is nonvanishing because of the unusual nature of particle-hole symmetry in this context and is not sensitive to the Berry phase. In contrast, we find that off-diagonal thermopower (Nernst effect) is directly related to the topological structure of the composite Fermi surface, vanishing for zero Berry phase and taking its maximal value for π Berry phase. In contrast, in purely electrical transport signatures, the Berry phase contributions appear as small corrections to a large background signal, making the Nernst effect a promising diagnostic of the Dirac nature of composite fermions.}, author = {Potter, Andrew C and Maksym Serbyn and Vishwanath, Ashvin K}, journal = {Physical Review X}, number = {3}, publisher = {American Physical Society}, title = {{Thermoelectric transport signatures of Dirac composite fermions in the half-filled Landau level}}, doi = {10.1103/PhysRevX.6.031026}, volume = {6}, year = {2016}, } @article{984, abstract = {The entanglement spectrum of the reduced density matrix contains information beyond the von Neumann entropy and provides unique insights into exotic orders or critical behavior of quantum systems. Here, we show that strongly disordered systems in the many-body localized phase have power-law entanglement spectra, arising from the presence of extensively many local integrals of motion. The power-law entanglement spectrum distinguishes many-body localized systems from ergodic systems, as well as from ground states of gapped integrable models or free systems in the vicinity of scale-invariant critical points. We confirm our results using large-scale exact diagonalization. In addition, we develop a matrix-product state algorithm which allows us to access the eigenstates of large systems close to the localization transition, and discuss general implications of our results for variational studies of highly excited eigenstates in many-body localized systems.}, author = {Maksym Serbyn and Alexios Michailidis and Abanin, Dmitry A and Papić, Zlatko}, journal = {Physical Review Letters}, number = {16}, publisher = {American Physical Society}, title = {{Power-law entanglement spectrum in many-body localized phases}}, doi = {10.1103/PhysRevLett.117.160601}, volume = {117}, year = {2016}, } @article{985, abstract = {We report on magnetotransport studies of dual-gated, Bernal-stacked trilayer graphene (TLG) encapsulated in boron nitride crystals. We observe a quantum Hall effect staircase which indicates a complete lifting of the 12-fold degeneracy of the zeroth Landau level. As a function of perpendicular electric field, our data exhibit a sequence of phase transitions between all integer quantum Hall states in the filling factor interval -8<ν<0. We develop a theoretical model and argue that, in contrast to monolayer and bilayer graphene, the observed Landau level splittings and quantum Hall phase transitions can be understood within a single-particle picture, but imply the presence of a charge density imbalance between the inner and outer layers of TLG, even at charge neutrality and zero transverse electric field. Our results indicate the importance of a previously unaccounted band structure parameter which, together with a more accurate estimate of the other tight-binding parameters, results in a significantly improved determination of the electronic and Landau level structure of TLG.}, author = {Campos, Leonardo C and Taychatanapat, Thiti and Maksym Serbyn and Surakitbovorn, Kawin N and Watanabe, Kenji and Taniguchi, Takashi and Abanin, Dmitry A and Jarillo-Herrero, Pablo}, journal = {Physical Review Letters}, number = {6}, publisher = {American Physical Society}, title = {{Landau Level Splittings, Phase Transitions, and Nonuniform Charge Distribution in Trilayer Graphene}}, doi = {10.1103/PhysRevLett.117.066601}, volume = {117}, year = {2016}, }