Characterizing the performance of continuous-variable Gaussian quantum gates

The required set of operations for universal continuous-variable quantum computation can be divided into two primary categories: Gaussian and non-Gaussian operations. Furthermore, any Gaussian operation can be decomposed as a sequence of phase-space displacements and symplectic transformations. Although Gaussian operations are ubiquitous in quantum optics, their experimental realizations generally are approximations of the ideal Gaussian unitaries. In this work, we study different performance criteria to analyze how well these experimental approximations simulate the ideal Gaussian unitaries. In particular, we find that none of these experimental approximations converge uniformly to the ideal Gaussian unitaries. However, convergence occurs in the strong sense, or if the discrimination strategy is energy bounded, then the convergence is uniform in the Shirokov-Winter energy-constrained diamond norm and we give explicit bounds in this latter case. We indicate how these energy-constrained bounds can be used for experimental implementations of these Gaussian unitaries in order to achieve any desired accuracy.Comment: v3: 26 pages, 10 figures, final version accepted for publication in Physical Review Researc

Information-theoretic aspects of the generalized amplitude damping channel

The generalized amplitude damping channel (GADC) is one of the sources of noise in superconducting-circuit-based quantum computing. It can be viewed as the qubit analogue of the bosonic thermal channel, and it thus can be used to model lossy processes in the presence of background noise for low-temperature systems. In this work, we provide an information-theoretic study of the GADC. We first determine the parameter range for which the GADC is entanglement breaking and the range for which it is anti-degradable. We then establish several upper bounds on its classical, quantum, and private capacities. These bounds are based on data-processing inequalities and the uniform continuity of information-theoretic quantities, as well as other techniques. Our upper bounds on the quantum capacity of the GADC are tighter than the known upper bound reported recently in [Rosati et al., Nat. Commun. 9, 4339 (2018)] for the entire parameter range of the GADC, thus reducing the gap between the lower and upper bounds. We also establish upper bounds on the two-way assisted quantum and private capacities of the GADC. These bounds are based on the squashed entanglement, and they are established by constructing particular squashing channels. We compare these bounds with the max-Rains information bound, the mutual information bound, and another bound based on approximate covariance. For all capacities considered, we find that a large variety of techniques are useful in establishing bounds.Comment: 33 pages, 9 figures; close to the published versio

Energy-Constrained Distinguishability Measures for Assessing Performance in Quantum Information Processing

The aim of this thesis is to develop a framework for assessing performance in quantum information processing with continuous variables. In particular, we focus on quantifying the fundamental limitations on communication and computation over bosonic Gaussian systems. Due to their infinite-dimensional structure, we make a realistic assumption of energy constraints on the input states of continuous-variable (CV) quantum operations. Our first contribution is to show that energy-constrained distinguishability measures can be used to establish tight upper bounds on the communication capacities of phase-insensitive, bosonic Gaussian channels -- thermal, amplifier, and additive-noise channels. We then prove that an optimal Gaussian input state for the energy-constrained, generalized channel divergence of two particular Gaussian channels is the two-mode squeezed vacuum state that saturates the energy constraint. Next, we develop theoretical and numerical tools based on energy-constrained distinguishability measures to quantify the accuracy in implementing Gaussian unitary operations. Finally, we propose an optimal test for the performance of CV quantum teleportation in terms of the energy-constrained channel fidelity between ideal CV teleportation and its experimental implementation. Here we prove that the optimal state for testing CV teleportation is an entangled superposition of twin-Fock states. These results are relevant for experiments that make use of Gaussian unitaries and CV teleportation

Conditional quantum one-time pad

Suppose that Alice and Bob are located in distant laboratories, which are connected by an ideal quantum channel. Suppose further that they share many copies of a quantum state $\rho_{ABE}$, such that Alice possesses the $A$ systems and Bob the $BE$ systems. In our model, there is an identifiable part of Bob's laboratory that is insecure: a third party named Eve has infiltrated Bob's laboratory and gained control of the $E$ systems. Alice, knowing this, would like use their shared state and the ideal quantum channel to communicate a message in such a way that Bob, who has access to the whole of his laboratory ($BE$ systems), can decode it, while Eve, who has access only to a sector of Bob's laboratory ($E$ systems) and the ideal quantum channel connecting Alice to Bob, cannot learn anything about Alice's transmitted message. We call this task the conditional one-time pad, and in this paper, we prove that the optimal rate of secret communication for this task is equal to the conditional quantum mutual information $I(A;B|E)$ of their shared state. We thus give the conditional quantum mutual information an operational meaning that is different from those given in prior works, via state redistribution, conditional erasure, or state deconstruction. We also generalize the model and method in several ways, one of which demonstrates that the negative tripartite interaction information $-I_{3}(A;B;E) = I(A;BE)-I(A;B)-I(A;E)$ of a tripartite state $\rho_{ABE}$ is an achievable rate for a secret-sharing task, i.e., the case in which Alice's message should be secure from someone possessing only the $AB$ or $AE$ systems but should be decodable by someone possessing all systems $A$, $B$, and $E$.Comment: v2: 16 pages, final version accepted for publication in Physical Review Letter

Commerce of Waste Elimination: A Buffer for Indian Sme’S

Waste elimination has benefited many industries in realising wealth creation by plugging undesired costs in operation and manufacturing excellence. Under the scenario of global competitiveness and dictative customer centric markets Indian SME’s which are backbone to Indian GDP, especially, automobile industries are striving hard for survival. These industries are slow in adopting and practising performance and efficiency based derives. In this context, waste elimination derives related to man, material, machine and method have been studied for  providing a competitive advantage and adding  fuel in enriching the bottomline of Indian SME’s.Fifty companies were surveyed by questionnaire and personal contact. Main findings of this article comprises of highlighting the present status of understanding the essence of subject matter, assessing the inadequacy of initiative taken by various companies and evaluating the hurdles in implementing waste management.Furthermore, findings lead to conclusion that imbueding the culture of waste elimination as a building block, organisations not only create revenue but also create value for the customers and end-users. It has been suggested that involvement of top management to push waste elimination derives at multi-levels in organisation will act as a catalyst in recuperating competitiveness and pulling off substantial wealth creation. Use of Information technology will excel the speed of such derives. Keywords : Waste Elimination; SME’s; Bottom-line; Operations; competitivenes

Remote preconditioning by aortic constriction: affords cardioprotection as classical or other remote ischemic preconditioning? Role of iNOS

Dose remote preconditioning by aortic constriction (RPAC) affords cardioprotection similar to classical or other remote ischemic preconditioning stimulus? Moreover study was also designed to investigate role of inducible nitric oxide synthase in remote preconditioning by aortic constriction. There are sufficient evidences that "ischemic preconditioning" has surgical applications and afford clinically relevant cardioprotection. Transient occlusion of circumflex artery, renal artery, limb artery or mesenteric artery preconditions the myocardium against ischemia reperfusion injury in case of ischemic heart disease leading to myocardial infraction. Here abdominal aorta was selected to produce RPAC. Four episodes of Ischemia-reperfusion of 5 min each to abdominal aorta produced RPAC by assessment of infract size, LDH and CK. These studies suggest RPAC produced acute (FWOP) and delayed (SWOP) cardioprotective effect. RPAC demonstrated a significant decrease in Ischemia-reperfusion induced release of LDH, CK and extent of myocardial infract size. L-NAME (10 mg/Kg i.v.), Aminoguanidine (150 mg/Kg s.c.), Aminoguanidine (300 mg/Kg s.c.), S-methyl isothiourea (3 mg/Kg i.v.), 1400W (1 mg/Kg i.v.) administered 10 min. before global ischemia reperfusion produced no marked effect. Aminoguanidine (150 mg/Kg s.c.), Aminoguanidine (300 mg/Kg s.c.), S-methyl isothiourea (3 mg/Kg i.v.), 1400W (1 mg/Kg i.v.) pretreatment after RPAC produced no significant effect on acute RPAC induced decrease in LDH, CK and infract size, whereas L-NAME (10 mg/Kg i.v.) increased RPAC induced decrease in LDH, CK and infract size. Most interesting observation is in delayed RPAC, where all NOS inhibitors pretreatment attenuate RPAC induced decrease in LDH, CK and infract size. In conclusions, "Remote preconditioning by aortic constriction" (RPAC) affords cardioprotection similar to classical or other remote ischemic preconditioning stimulus. Moreover, late or delayed phase of RPAC has been mediated by inducible nitric oxide synthase (iNOS) whereas it has not involved in acute RPAC

Ranking Volatility in Building Energy Consumption Using Ensemble Learning and Information Entropy

Given the rise in building energy consumption and demand worldwide, energy inefficiency detection has become extremely important. A significant portion of the energy used in commercial buildings is wasted as a result of poor maintenance, degradation or improperly controlled equipment. Most facilities employ sensors to track energy consumption across multiple buildings. Smart fault detection and diagnostic systems use various anomaly detection techniques to discover point anomalies in consumption. While these systems work reasonably well in detecting equipment anomalies over short-term intervals, further exploration is needed in finding methods that consider long-term consumption to detect anomalous buildings. This paper presents a novel approach for a multi-building campus to rank and visualize the long-term volatility of building consumption. This allows for the optimal allocation of limited time and resources for the detection and resolution of energy waste. The proposed method first classifies daily consumption into 5 classes using an ensemble learner and then calculates the information entropy on the resulting classification set to determine volatility. The ensemble learner receives input from a K-Nearest Neighbor classifier, a Random Forest classifier and an Artificial Neural Network. In general, buildings are expected to keep the same energy profile over time, all else being equal. Buildings that frequently change energy profiles are ranked and flagged by the system for review, which would call for the next step to reduce waste and costs and to increase the sustainability of buildings. Data on energy consumption for 132 buildings is obtained from energy management at the Georgia Institute of Technology. Experimental results show the effectiveness of the proposed approach

Sexual dimorphism: metric measurements based study in human talus bone

 Background: Identification is the act of establishing the identity of an individual. This is a dynamic process and human remains in form of bones can serve as an excellent tool for establishing the sexual identity of the deceased, along with other methods such as DNA, fingerprints, blood group identification etc. Metric analysis of various bones can serve as a viable alternative in cases when morphological analysis is not possible due to damage to the skeletal remains or as an additive analytical tool to establish a positive identity.Methods: Metric analysis of various parameters of randomly selected 100 pairs of human talus bones (50 male and 50 female) as a means of establishing sexual identity from skeletal remains obtained from unidentified and unclaimed dead bodies brought for autopsy.Results: In the present study we found that the values of all the various dimensions measured were higher among the male subjects as compared to that in female samples as was expected. On further analysis, this difference was found to be statistically significant (p<0.001). For the right sided and left sided talus bone, the probable accuracy for various parameters ranged between 83.3% to 100% each, thus indicating strong correlation between sex of the subject and various measurements.Conclusions: The tarsal and their dimensions are highly sexually dimorphic and are useful in determining sex in individuals of this region

Drug Related Hypertension: A Review on an Unappreciated Cause of Blood Pressure Increase

Blood pressure elevation is known to be a determining risk factor for cardiovascular disease and mortality. Although blood pressure increase has many causative factors, numerous drugs have also been reported to increase blood pressure. Drugs are often overlooked as a reason of hypertension. A few medications that usually help to reduce blood pressure may increase blood pressure paradoxically or may lead to blood pressure elevation on discontinuation due to a rebound effect. Detailed evaluation of patient’s medical therapy may help to identify the culprit drug. Discontinuation of the causative agent is recommended once the drug induced hypertension has been identified. The present review summarizes the therapeutic agents that can induce hypertension and would allow the clinician to recognize this entity and to take the appropriate therapeutic measures