Quantum Speed Limit For Mixed States Using Experimentally Realizable Metric

The minimal time required for a system to evolve between two different states is an important notion for developing ultra-speed quantum computer and communication channel. Here, we introduce a new metric for non-degenerate density operator evolving along unitary orbit and show that this is experimentally realizable operation dependent metric on quantum state space. Using this metric, we obtain the geometric uncertainty relation that leads to a new quantum speed limit. Furthermore, we argue that this gives a tighter bound for the evolution time compared to any other bound. We also obtain a Levitin kind of bound for mixed states. We propose how to measure this new distance and speed limit in quantum interferometry. Finally, the lower bound for the evolution time of a quantum system is studied for any completely positive trace preserving map using this metric.Comment: Latex, 8+\epsilon pages, 1 Fig accepted in PL

Non-Local Advantage of Quantum Coherence

A bipartite state is said to be steerable if and only if it does not have a single system description, i.e., the bipartite state cannot be explained by a local hidden state model. Several steering inequalities have been derived using different local uncertainty relations to verify the ability to control the state of one subsystem by the other party. Here, we derive complementarity relations between coherences measured on mutually unbiased bases using various coherence measures such as the $l_1$-norm, relative entropy and skew information. Using these relations, we derive conditions under which non-local advantage of quantum coherence can be achieved and the state is steerable. We show that not all steerable states can achieve such advantage.Comment: 8 pages, protocol modified, To appear in PRA-Rapid Communication

Estimates for the nonlinear viscoelastic damped wave equation on compact Lie groups

Let $G$ be a compact Lie group. In this article, we investigate the Cauchy problem for a nonlinear wave equation with the viscoelastic damping on $G$. More preciously, we investigate some $L^2$-estimates for the solution to the homogeneous nonlinear viscoelastic damped wave equation on $G$ utilizing the group Fourier transform on $G$. We also prove that there is no improvement of any decay rate for the norm $\|u(t,\cdot)\|_{L^2(G)}$ by further assuming the $L^1(G)$-regularity of initial data. Finally, using the noncommutative Fourier analysis on compact Lie groups, we prove a local in time existence result in the energy space $\mathcal{C}^1([0,T],H^1_{\mathcal L}(G)).$Comment: 16 pages. arXiv admin note: text overlap with arXiv:2207.0442

Projecting Climate and Land Use Change Impacts on Actual Evapotranspiration for the Narmada River Basin in Central India in the Future

Assessment of actual evapotranspiration (ET) is essential as it controls the exchange of water and heat energy between the atmosphere and land surface. ET also influences the available water resources and assists in the crop water assessment in agricultural areas. This study involves the assessment of spatial distribution of seasonal and annual ET using Surface Energy Balance Algorithm for Land (SEBAL) and provides an estimation of future changes in ET due to land use and climate change for a portion of the Narmada river basin in Central India. Climate change effects on future ET are assessed using the ACCESS1-0 model of CMIP5. A Markov Chain model estimated future land use based on the probability of changes in the past. The ET analysis is carried out for the years 2009-2011. The results indicate variation in the seasonal ET with the changed land use. High ET is observed over forest areas and crop lands, but ET decreases over crop lands after harvest. The overall annual ET is high over water bodies and forest areas. ET is high in the premonsoon season over the water bodies and decreases in the winter. Future ET in the 2020s, 2030s, 2040s, and 2050s is shown with respect to land use and climate changes that project a gradual decrease due to the constant removal of the forest areas. The lowest ET is projected in 2050. Individual impact of land use change projects decreases in ET from 1990 to 2050, while climate change effect projects increases in ET in the future due to rises in temperature. However, the combined impacts of land use and climate changes indicate a decrease in ET in the future

Observation of multiple van Hove singularities and correlated electronic states in a new topological ferromagnetic kagome metal NdTi3Bi4

Kagome materials have attracted enormous research interest recently owing to its diverse topological phases and manifestation of electronic correlation due to its inherent geometric frustration. Here, we report the electronic structure of a new distorted kagome metal NdTi3Bi4 using a combination of angle resolved photoemission spectroscopy (ARPES) measurements and density functional theory (DFT) calculations. We discover the presence of two at bands which are found to originate from the kagome structure formed by Ti atoms with major contribution from Ti dxy and Ti dx2-y2 orbitals. We also observed multiple van Hove singularities (VHSs) in its electronic structure, with one VHS lying near the Fermi level EF. In addition, the presence of a surface Dirac cone at the G point and a linear Dirac-like state at the K point with its Dirac node lying very close to the EF indicates its topological nature. Our findings reveal NdTi3Bi4 as a potential material to understand the interplay of topology, magnetism, and electron correlation.Comment: 7 pages, 4 figure

Discovery of a magnetic Dirac system with large intrinsic non-linear Hall effect

Magnetic materials exhibiting topological Dirac fermions are attracting significant attention for their promising technological potential in spintronics. In these systems, the combined effect of the spin-orbit coupling and magnetic order enables the realization of novel topological phases with exotic transport properties, including the anomalous Hall effect and magneto-chiral phenomena. Herein, we report experimental signature of topological Dirac antiferromagnetism in TaCoTe2 via angle-resolved photoelectron spectroscopy (ARPES) and first-principles density functional theory (DFT) calculations. In particular, we find the existence of spin-orbit coupling-induced gaps at the Fermi level, consistent with the manifestation of a large intrinsic non-linear Hall conductivity. Remarkably, we find that the latter is extremely sensitive to the orientation of the N\'eel vector, suggesting TaCoTe2 a suitable candidate for the realization of non-volatile spintronic devices with an unprecedented level of intrinsic tunability

Observation of multiple flat bands and topological Dirac states in a new titanium based slightly distorted kagome metal YbTi3Bi4

Kagome lattices have emerged as an ideal platform for exploring various exotic quantum phenomena such as correlated topological phases, frustrated lattice geometry, unconventional charge density wave orders, Chern quantum phases, superconductivity, etc. In particular, the vanadium based nonmagnetic kagome metals AV3Sb5 (A= K, Rb, and Cs) have seen a flurry of research interest due to the discovery of multiple competing orders. Here, we report the discovery of a new Ti based kagome metal YbTi3Bi4 and employ angle-resolved photoemission spectroscopy (ARPES), magnetotransport in combination with density functional theory calculations to investigate its electronic structure. We reveal spectroscopic evidence of multiple flat bands arising from the kagome lattice of Ti with predominant Ti 3d character. Through our calculations of the Z2 indices, we have identified that the system exhibits topological nontriviality with surface Dirac cones at the Gamma point and a quasi two-dimensional Dirac state at the K point which is further confirmed by our ARPES measured band dispersion. These results establish YbTi3Bi4 as a novel platform for exploring the intersection of nontrivial topology, and electron correlation effects in this newly discovered Ti based kagome lattice.Comment: 8 pages, 5 figure

Seeding the Green Future - Participatory organic cotton breeding

BackgroundWorldwide, India is the most important country for organic cotton production with 67% market share. In India, organic cotton production is challenged by 95% genetically modified (GM) cotton cultivation.Public breeding and seed multiplication were neglected and local non-GM seeds supply were eroded. With the continuous growth of the organic market it is important to maintain non-GM germplasm, to enlarge the offer of organic cultivars with a better performance that meet the demand of the market, and to rebuild the seed sovereignty of organic smallholder cotton farmers. Participatory breeding of Gossypiumhirsutumand traditionalG. arboreumcotton offers a great opportunity for developing locally adapted cultivars for increasing genetic diversity