- Who Discovered DNA?This linking of a small group of names to scientific discoveries is not uncommon; quantum mechanics, with Schrödinger and Heisenberg, the ... read more
- Obituary: David Thouless, Scottish scientist who won the Nobel prize for
**physics**... fellow scientists said Dr Thouless's research helped create a “paradigm shift in quantum physics” comparable to the ancient Greeks' first suggestion ... read more - Perfect State Transfer on Weighted Graphs of the Johnson Scheme. (arXiv:1904.08838v1 [math.CO])We characterize perfect state transfer on real-weighted graphs of the Johnson scheme $mathcal{J}(n,k)$. Given $mathcal{J}(n,k)={A_1, A_2, cdots, A_k}$ and $A(X) = w_0A_0 + cdots + w_m A_m$, we show, using classical number theory results, that $X$ has perfect state transfer at time $tau$ if and only if $n=2k$, $mge 2^{lfloor{log_2(k)} ... read more
- A doubly exponential upper bound on noisy EPR states for binary games. (arXiv:1904.08832v1 [quant-ph])This paper initiates the study of a class of entangled-games, mono-state games, denoted by $(G,psi)$, where $G$ is a two-player one-round game and $psi$ is a bipartite state independent of the game $G$. In the mono-state game $(G,psi)$, the players are only allowed to share arbitrary copies of $psi$. This ... read more
- A new density functional method for electronic structure calculation of atoms and molecules. (arXiv:1904.08806v1 [physics.chem-ph])This chapter concerns with the recent development of a new DFT methodology for accurate, reliable prediction of many-electron systems. Background, need for such a scheme, major difficulties encountered, as well as their potential remedies are discussed at some length. Within the realm of non relativistic Hohenberg-Kohn-Sham (HKS) DFT and making ... read more
- Practical security of continuous-variable quantum key distribution with reduced optical attenuation. (arXiv:1904.08777v1 [quant-ph])In a practical CVQKD system, the optical attenuator can adjust the Gaussian-modulated coherent states and the local oscillator signal to an optimal value for guaranteeing the security of the system and optimizing the performance of the system. However, the performance of the optical attenuator may deteriorate due to the intentional ... read more
- Decoherence of dipolar spin ensembles in diamond. (arXiv:1904.08763v1 [quant-ph])We present a combined theoretical and experimental study of solid-state spin decoherence in an electronic spin bath, focusing specifically on ensembles of nitrogen vacancy (NV) color centers in diamond and the associated substitutional nitrogen spin bath. We perform measurements of NV spin free induction decay times $T_2^*$ and spin-echo coherence ... read more
- Inferring crystal electronic properties from experimental data sets through Semidefinite Programming. (arXiv:1904.08757v1 [cond-mat.mtrl-sci])Constructing a quantum description of crystals from scattering experiments is of paramount importance to explain their macroscopic properties and to evaluate the pertinence of theoretical ab-initio models. While reconstruction methods of the one-electron reduced density matrix have already been proposed, they are usually tied to strong assumptions that limit and ... read more
- Gentle Measurement of Quantum States and Differential Privacy. (arXiv:1904.08747v1 [quant-ph])In differential privacy (DP), we want to query a database about n users, in a way that "leaks at most eps about any individual user," even conditioned on any outcome of the query. Meanwhile, in gentle measurement, we want to measure n quantum states, in a way that "damages the ... read more
- Parity-Enhanced Quantum Optimal Measurements. (arXiv:1904.08738v1 [quant-ph])We find a large class of pure and mixed input states with which the phase estimation precision saturates the Cramer-Rao bound under the compound measurements of parity and particle number. We further propose a quantum-phase-estimation protocol for arbitrary input states, through which the precision achieved is always higher than or ... read more
- Almost thermal operations: inhomogeneous reservoirs. (arXiv:1904.08736v1 [quant-ph])The resource theory of thermal operations explains the state transformations that are possible in a very specific thermodynamic setting: there is only one thermal bath, auxiliary systems can only be in corresponding thermal state (free states), and the interaction must commute with the free Hamiltonian (free operation). In this paper ... read more
- Optimal gauge for the multimode Rabi model in circuit QED. (arXiv:1904.08735v1 [quant-ph])In circuit QED, a Rabi model can be derived by truncating the Hilbert space of the anharmonic qubit coupled to a linear, reactive environment. This truncation breaks the gauge invariance present in the full Hamiltonian. We analyze the determination of an optimal gauge such that the differences between the truncated ... read more
- DFT calculations of atoms and molecules in Cartesian grids. (arXiv:1904.08729v1 [physics.chem-ph])Density functional theory (DFT) has emerged as one of the most versatile and lucrative approaches in electronic structure calculations of many-electron systems in past four decades. Here we give an account of the development of a variational DFT method for atoms and molecules emph{completely} in a Cartesian grid. The non-relativistic ... read more