We cast observable measure of quantum coherence or asymmetry as a resource to control the quantum... more We cast observable measure of quantum coherence or asymmetry as a resource to control the quantum speed limit (QSL) for unitary evolutions. For non-unitary evolutions, QSL depends on that of the state of the system and environment together. We show that the product of the time bound and the coherence (asymmetry) or the quantum part of the uncertainty behaves in a geometric way under partial elimination and classical mixing of states. These relations give a new insight to the quantum speed limit. We also show that our bound is experimentally measurable and is tighter than various existing bounds in the literature.
Our project aims at supporting the creation of sustainable and meaningful longer-term human-robot... more Our project aims at supporting the creation of sustainable and meaningful longer-term human-robot relationships through the creation of embodied robots with face recognition and natural language dialogue capabilities, which exploit and publish social information available on the web (Facebook). Our main underlying experimental hypothesis is that such relationships can be significantly enhanced if the human and the robot are gradually creating a pool of shared episodic memories that they can co-refer to ("shared memories"), and if they are both embedded in a social web of other humans and robots they both know and encounter ("shared friends"). In this paper, we are presenting such a robot, which as we will see achieves two significant novelties.
Employing the Pauli matrices, we have constructed a set of operators, which can be used to distin... more Employing the Pauli matrices, we have constructed a set of operators, which can be used to distinguish six inequivalent classes of entanglement under SLOCC (stochastic local operation and classical communication) for three-qubit pure states. These operators have very simple structure and can be obtained from the Mermin's operator with suitable choice of directions. Moreover these operators may be implemented in an experiment to distinguish the types of entanglement present in a state. We show that the measurement of only one operator is sufficient to distinguish GHZ class from rest of the classes. It is also shown that it is possible to detect and classify other classes by performing a small number of measurements. We also show how to construct such observables in any basis. We also consider a few mixed states to investigate the usefulness of our operators. Furthermore, we consider the teleportation scheme of Lee et al. [19] and show that the partial tangles and hence teleportation fidelity can be measured. We have also shown that these partial tangles can also be used to classify genuinely entangled state, biseparable state and separable state.
Developments in healthcare delivery systems are focusing on improved quality of care and patient ... more Developments in healthcare delivery systems are focusing on improved quality of care and patient satisfaction. Automated medication management on a mobile service robot is part of our interdisciplinary Healthbots research project, and has the potential to address both areas. The robotic medication reminding system is the result of an analysis of the workflow in medication management and a systematic application of the workflow to an interactive mobile robot. The robot is being evaluated to develop a better understanding of the technology required to address the safety and adherence issues of medication management for seniors living independently in a retirement village. Medication data and instructions presented during interaction need to be programmed by end users according to the medication. Changes such as the schedule, the names of drugs, and constraints in taking the medication, are periodically updated by the caregiver after the medication is prescribed by the doctor and dispatched by the pharmacist. This paper presents an analysis of the end user tools and the software architecture essential to complete this medication workflow. Initial prototypes of the software were used in a pilot study at a retirement village. The pilot system can support the quality of care provided to the older people and prevent medication errors. The contribution the paper is a new analysis and novel design for enabling role based customization for robotic medication reminding. These contributions will assist in the technical decision making of developers involved in implementing service robots for similar tasks.
Natural fibres are partly replacing currently used synthetic fibres as reinforcement for polymer ... more Natural fibres are partly replacing currently used synthetic fibres as reinforcement for polymer composites. Jute fibre bundles were high-cellulose-content modified by alkali treatment, while the bagasse fibre bundles were modified by creating quinones in the lignin portions of fibre surfaces and reacting them with furfuryl alcohol (FA) to increase their adhesiveness. The effects of different fibre bundle loading and modification of bagasse fibre surfaces in hybrid fibre reinforced epoxy composites have been studied. The role of fibre/matrix interactions in chemically modified hybrid composites were investigated using Differential Scanning Calorimeter, Differential Thermo Gravimetry, and a Universal Tensile Machine and compared with those of unmodified bagasse fibre bundles incorporated with modified jute fibre bundles reinforced hybrid composites. Fibre surface modification reduced the hydrophilicity of fibre bundles, and significantly increased mechanical properties of hybrid comp...
Uncertainty relations play a significant role in drawing a line between classical physics and qua... more Uncertainty relations play a significant role in drawing a line between classical physics and quantum physics. Since the introduction by Heisenberg, these relations have been considerably explored. However, the effect of quantum entanglement on uncertainty relations was not probed. Berta et al. [Nature Physics 6, 659-662 (2010)] removed this gap by deriving a conditional-entropic uncertainty relation in the presence of quantum entanglement. In the same spirit, using inferred-variance, we formulate uncertainty relations in the presence of entanglement for general two-qubit systems and arbitrary observables. We derive lower bounds for the sum and product inferred-variance uncertainty relations. Strikingly, we can write the lower bounds of these inferred-variance uncertainty relations in terms of measures of entanglement of two-qubit states, as characterized by concurrence, or G function. Presumably, the presence of entanglement in the lower bound of inferred-variance uncertainty relation is new and unique. We also explore the violation of local uncertainty relations in this context and an interference experiment. Furthermore, we discuss possible applications of these uncertainty relations.
We formulate the conditional-variance uncertainty relations for general qubit systems and arbitra... more We formulate the conditional-variance uncertainty relations for general qubit systems and arbitrary observables via the inferred uncertainty relations. We find that the lower bounds of these conditional-variance uncertainty relations can be written in terms of entanglement measures including concurrence, $G$ function, quantum discord quantified via local quantum uncertainty in different scenarios. We show that the entanglement measures reduce these bounds, except quantum discord which increases them. Our analysis shows that these correlations of quantumness measures play different roles in determining the lower bounds for the sum and product conditional variance uncertainty relations. We also explore the violation of local uncertainty relations in this context and in an interference experiment.
Distinguishing physical processes is one of the fundamental problems in quantum physics. Although... more Distinguishing physical processes is one of the fundamental problems in quantum physics. Although distinguishability of quantum preparations and quantum channels have been studied considerably, distinguishability of quantum measurements remains largely unexplored. We investigate the problem of single-shot discrimination of quantum measurements using two strategies, one based on single quantum systems and the other one based on entangled quantum systems. First, we formally define both scenarios. We then construct sets of measurements (including non-projective) in arbitrary finite dimensions that are perfectly distinguishable within the second scenario using quantum entanglement, while not in the one based on single quantum systems. Furthermore, we show that any advantage in measurement discrimination tasks over single systems is a demonstration of Einstein–Podolsky–Rosen ‘quantum steering’. Alongside, we prove that all pure two-qubit entangled states provide an advantage in a measure...
It is well known that certain quantum correlations like quantum steering exhibit a monogamous rel... more It is well known that certain quantum correlations like quantum steering exhibit a monogamous relationship. In this paper, we exploit the asymmetric nature of quantum steering and show that there exist states which exhibit a kind of polygamous correlation, where the state of one party, Alice, can be steered only by the joint effort of the other two parties, Bob and Charlie. %This is in any way not in contradiction with the existing literature. Since, instead of looking at whether Alice can steer both Bob and Charlie simultaneously or not, we investigate whether there exists states such that Alice can only be steered by Bob and Charlie together. As an example, we explicitly single out a particular set of $3$ qubit states which exhibit polygamous relationship and also provide a recipe to identify the complete set of such states. We also provide a possible application of such states to an information theoretic task, we term as quantum key authentication (QKA). QKA can also be used in c...
2012 4th IEEE RAS & EMBS International Conference on Biomedical Robotics and Biomechatronics (BioRob), 2012
This paper presents the second version of a mobile service robot (HealthBot) designed for older p... more This paper presents the second version of a mobile service robot (HealthBot) designed for older people. The lessons learned from studies of the first version of the robot at a retirement village, and design decisions for the second version, are discussed. Technical requirements of field trials, a focus on cognitive human-robot interactions, the importance of working together in a multidisciplinary team, and the necessity for rapid iterative development suggested a new software framework. The features of new framework are discussed and implementation details are presented. Details of field trials and user acceptance results are presented. Results are promising for older-user acceptance of the robot.
Duars has wider potential in the development of tea tourism as a separate industry. Government of... more Duars has wider potential in the development of tea tourism as a separate industry. Government of West Bengal has focused on Tea Tourism in making it popular among tourist. Duars is land of natural beauty of mountain, dense green forest, waterfall, river, cave which act as a pull factor for tourist attraction. The tea garden adds new dimensions to the beauty of Duars. Tea tourism has been flourished with countries like China, Srilanka and Kenya. It is now spreading in India. Tea tourism which integrates the natural environment of tea garden, tea leaves plucking, tea production, tea packaging and tea labour-culture. It is a new type of tourism which covers different types of tourist entertainment such as sightseeing viewing, roaming in tea garden, having tea in tea stall from different tea factory, watching evening tea-labour cultural performance etc.
Nano Trends-A Journal of Nano Technology & Its Applications, 2020
Silver had been used by human thousands of years ago as various types of medicines (Rasaratna Sam... more Silver had been used by human thousands of years ago as various types of medicines (Rasaratna Samuccahay, Bhagbhatta). As the years passes more scientific uses of silver metals had been seen as the human civilization progresses. After the discovery of nano technology Silver is being used in a variety of ways .Nano particles exhibits less toxicity as compared to their ionic counterpart. Nowadays silver is used in various forms colloidal silver Nanoparticle (AgNPs) is one of the main form of silver, Today is being used in Human body considering toxicity level Colloidal Silver is being used as a new antimicrobial agent having broad microbial activity against Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa and Salmonella typhi (Nauran H Assar and Hayam M Hamuoda,2010). Domestic cleaning products enhanced with antimicrobial silver have been patented (Minner and Eatough 2007). Viral infections make disparate need for the development of safe and potent alternatives to conventional antiviral drugs. In now days, nanoscale materials have emerged as novel antiviral agents for the enormous possibilities offered by their unique chemical and physical properties. Colloidal silver or silver nanoparticle has its own antimicrobial properties to combat all types of viruses including human immunodeficiency virus, hepatitis B virus, herpes simplex virus, flu virus etc. Our main focus through this review is to literate the people about this rediscovered material and it has antimicrobial properties which will be very much helpful for the society in long run.
International Journal of Quantum Information, 2020
We consider the problem of estimating the spatial separation between two mutually incoherent poin... more We consider the problem of estimating the spatial separation between two mutually incoherent point light sources using the super-resolution imaging technique based on spatial mode demultiplexing (SPADE) with noisy detectors. We show that in the presence of noise, the resolution of the measurement is limited by the signal-to-noise ratio (SNR) and the minimum resolvable spatial separation has a characteristic dependence of [Formula: see text]. Several detection techniques, including direct photon counting, as well as homodyne and heterodyne detection are considered.
It is well known that certain quantum correlations like quantum steering exhibit a monogamous rel... more It is well known that certain quantum correlations like quantum steering exhibit a monogamous relationship. In this paper, we exploit the asymmetric nature of quantum steering and show that there exist states which exhibit a polygamous correlation, known as collective correlation [He and Reid, Phys. Rev. Lett. 111, 250403 (2013)], where the state of one party, Alice, can be steered only by the joint effort of the other two parties, Bob and Charlie. As an example, we explicitly single out a particular set of 3 qubit states which exhibit this polygamous relationship, known as collective steerability. We provide a recipe to identify the complete set of such states. We also provide a possible application of such states to an information theoretic task, termed as quantum key authentication (QKA) protocol. QKA can also be used in conjunction with other well known cryptography protocols to improve their security and we provide one such example with quantum private comparison (QPC).
We investigate the coherence of quantum channels using the Choi-Jamiołkowski isomorphism. The rel... more We investigate the coherence of quantum channels using the Choi-Jamiołkowski isomorphism. The relation between the coherence and the purity of the channel respects a duality relation. It characterizes the allowed values of coherence when the channel has certain purity. This duality has been depicted via the Coherence-Purity (Co-Pu) diagrams. In particular, we study the quantum coherence of the unital and non-unital qubit channels and find out the allowed region of coherence for a fixed purity. We also study coherence of different incoherent channels, namely, incoherent operation (IO), strictly incoherent operation (SIO), physical incoherent operation (PIO) etc. Interestingly, we find that the allowed region for different incoherent operations maintain the relation P IO ⊂ SIO ⊂ IO. In fact, we find that if PIOs are coherence preserving operations (CPO), its coherence is zero otherwise it has unit coherence and unit purity. Interestingly, different kinds of qubit channels can be distinguished using the Co-Pu diagram. The unital channels generally do not create coherence whereas some nonunital can. All coherence breaking channels are shown to have zero coherence, whereas, this is not usually true for entanglement breaking channels. It turns out that the coherence preserving qubit channels have unit coherence. Although the coherence of the Choi matrix of the incoherent channels might have finite values, its subsystem contains no coherence. This indicates that the incoherent channels can either be unital or nonunital under some conditions.
To explore the properties of a two-qubit mixed state, we consider quantum teleportation. The fide... more To explore the properties of a two-qubit mixed state, we consider quantum teleportation. The fidelity of a teleported state depends on the resource state purity and entanglement, as characterized by concurrence. Concurrence and purity are functions of state parameters. However, it turns out that a state with larger purity and concurrence, may have comparatively smaller fidelity. By computing teleportation fidelity, concurrence and purity for two-qubit X-states, we show it explicitly. We further show that fidelity changes monotonically with respect to functions of parameters -other than concurrence and purity. A state with smaller concurrence and purity, but larger value of one of these functions has larger fidelity. These functions, thus characterize nonlocal classical and/or quantum properties of the state that are not captured by purity and concurrence alone. In particular, concurrence is not enough to characterize the entanglement properties of a two-qubit mixed state.
Employing the Pauli matrices, we have constructed a set of operators, which can be used to distin... more Employing the Pauli matrices, we have constructed a set of operators, which can be used to distinguish six inequivalent classes of entanglement under SLOCC (stochastic local operation and classical communication) for three-qubit pure states. These operators have very simple structure and can be obtained from the Mermin's operator with suitable choice of directions. Moreover these operators may be implemented in an experiment to distinguish the types of entanglement present in a state. We show that the measurement of only one operator is sufficient to distinguish GHZ class from rest of the classes. It is also shown that it is possible to detect and classify other classes by performing a small number of measurements. We also show how to construct such observables in any basis. We also consider a few mixed states to investigate the usefulness of our operators. Furthermore, we consider the teleportation scheme of Lee et al. [19] and show that the partial tangles and hence teleportation fidelity can be measured. We have also shown that these partial tangles can also be used to classify genuinely entangled state, biseparable state and separable state.
We cast observable measure of quantum coherence or asymmetry as a resource to control the quantum... more We cast observable measure of quantum coherence or asymmetry as a resource to control the quantum speed limit (QSL) for unitary evolutions. For non-unitary evolutions, QSL depends on that of the state of the system and environment together. We show that the product of the time bound and the coherence (asymmetry) or the quantum part of the uncertainty behaves in a geometric way under partial elimination and classical mixing of states. These relations give a new insight to the quantum speed limit. We also show that our bound is experimentally measurable and is tighter than various existing bounds in the literature.
To investigate whether robots could reduce resident sleeping and stimulate activity in the lounge... more To investigate whether robots could reduce resident sleeping and stimulate activity in the lounges of an older persons' care facility. Non-randomised controlled trial over a 12-week period. The intervention involved situating robots in low-level and high-dependency ward lounges and a comparison with similar lounges without robots. A time sampling observation method was utilised to observe resident behaviour, including sleep and activities over periods of time, to compare interactions in robot and no robot lounges. The use of robots was modest; overall 13% of residents in robot lounges used the robot. Utilisation was higher in the low-level care lounges; on average, 23% used the robot, whereas in high-level care lounges, the television being on was the strongest predictor of sleep. This study found that having robots in lounges was mostly a positive experience. The amount of time residents slept during the day was significantly less in low-level care lounges that had a robot.
A pilot study to understand requirements of a shopping mall robot
Proceedings of the 6th international conference on Human-robot interaction, 2011
... Mall Robot Chandan Datta Department of Electrical and Computer Engineering University of Auck... more ... Mall Robot Chandan Datta Department of Electrical and Computer Engineering University of Auckland New Zealand chandan.datta@auckland.ac.nz Anuj Kapuria Hitech Robotic Systemz Ltd Gurgaon, India anuj.kapuria@gmail.com ...
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