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Entanglement: Engineering and its Dynamical Studies in Dissipative Environments

Thesis Info

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External Link

Author

Tahira, Rabia

Program

PhD

Institute

COMSATS University Islamabad

City

Islamabad

Province

Islamabad.

Country

Pakistan

Thesis Completing Year

2012

Thesis Completion Status

Completed

Subject

Physics

Language

English

Link

http://prr.hec.gov.pk/jspui/handle/123456789/1741

Added

2021-02-17 19:49:13

Modified

2024-03-24 20:25:49

ARI ID

1676726065681

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This thesis covers the two inter-related topics of recent research in the field of quantum information theory. One topic is about the robust generation of entanglement among Gaussian states in quantum optical passive and active devices like beam splitters and quantum beat lasers and the other topic is about the degradation of entanglement due to decoherence when entangled states interact with the surrounding environments. The subject of entanglement generation is studied in continuous variable systems for two initial separable single-mode Gaussian states in beam splitters and in quantum beat lasers. As a general treatment, one single-mode Gaussian state is defined in terms of arbitrary values of nonclassicality and purity while the other single-mode Gaussian state is considered as the thermal field. The role of different parameters in the presence of thermal noise on the entanglement generation is explored, for example, the nonclassicality and purity of single-mode Gaussian state; and angle of beam splitter or driving field strength in quantum beat laser are important for robust entanglement generation. For entanglement analysis, logarithmic negativity is implied as a measure of entanglement for two-mode Gaussian states. Second topic investigates the dynamics of a class of initial entangled states in dissipative environments. It is the study of decoherence mechanism in different systems and is crucial as real systems always interact with the surrounding environments. The dynamics of the two-qubit atomic systems and high-dimensional bipartite field states inside the two high-Q cavities surrounded by thermal environment are investigated. The two-qubit atomic systems are explored as both interacting (close) and non-interacting (distant) systems. In the interacting systems, atoms are considered close together so that the atoms may exchange energy, thus the role of collective damping and dipole-dipole interaction becomes important. It is also noted that entanglement may be generated for initial separable states in thermal environment. Wootters concurrence is used as a quantitative measure of entanglement for two-qubit atomic systems. For the entangled bipartite field states in thermal environment, the high dimensional states as non-interacting systems are studied. It is concluded that sudden death of entanglement (SDE) always occurs in non-interacting systems in thermal environments. The increase in the temperature of the environment results in earlier disappearance of entanglement. For entanglement analysis, negativity is used for high-dimensional entangled field states in high-Q cavities.
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غلام فرید کاٹھیا اور شاہد رضوان کے افسانے

غلام فرید کاٹھیا اور شاہد رضوان کے افسانے
( تقابلی جائزہ)
غلام فرید کاٹھیا
مہرغلام فرید کاٹھیا کا شمار دور جدید کے فکشن نگاروں میں ہوتا ہے۔ آپ اردو ادب کے ان ابھرتے ہوئے افسانہ نگاروں میں شمار ہوتے ہیں کہ جنہوں نے اپنے افسانوں کے ذریعے پسماندہ طبقے کے مسائل کی بھرپورعکاسی کی ہے۔ مہرغلام فرید کاٹھیا کے اب تک " تین"افسانوی مجموعے"لمحوں کی قید"،"سرسوں کا پھول"اور"سفید تتلیوں کا ہار" شائع ہو چکے ہیں۔مہرغلام فرید کاٹھیا نے اپنے ان تینوں افسانوی مجموعوں میں محتاجوں،غریبوں،لاچاروں، اور مظلوم عورتوں پر ہونے والے مظالم پر قلم اٹھایا ہے۔ آپ کے تمام افسانے غریبوں کے استحصال اور وڈیروں کے ہاتھوں پسماندہ طبقے سے کی جانے والی ناانصافیوں کا منہ بولتا ثبوت ہیں۔ ازل ہی سے بر سرِ اقتدار طبقے نے اپنے سے کم حیثیت لوگوں پر ظلم و جبر کے پہاڑ توڑے ہیں۔امیروں نے غریبوں کو اپنے مفادات کی غرض سے فقط استعمال ہی کیا ہے۔ لوگوں سے تھوڑی اجرت کے بدلے زیادہ مشقت کروائی جاتی رہی ہے۔ پسماندہ طبقے کی غریبی کو مذاق بنا کرحقداروں سے ان کے جائز حقوق چھینے جاتے رہے ہیں۔کارل مارکس کے نظریہ مارکسزم اور ترقی پسند تحریک سے وابستہ افسانہ نگاروں نے جب غریبوں پر ہونے والے جبر و زیادتی کومحسوس کیا تو ان افسانہ نگاروں نے معاشرے کی اصلاح کے لئے غریبوں کے حق میں آواز بلند کرنا شروع کر دی۔ مزدوروں،کسانوں اور غریبوں کو کم اجرت دینے،غریبوں کے غریب تر اور سرمایہ داروں کے امیر تر بنتے جانے کے خلاف جن مصنفین نے اپنی تحریروں میں پسماندہ طبقے کی مشکلات کے حل کے لیے قلم اٹھایا ان میں پریم چند، سعادت حسن منٹو،احمد ندیم قاسمی،عصمت چغتائی،راجندر سنگھ بیدی،اختر حسین رائے پوری وغیرہ شامل ہیں۔
جس طرح ماضی میں دیگر مصنفین و افسانہ نگاروں نے غریبوں کے حق کے لئے قلمی جہاد...

Effect of Microwave Power and Time on Total Phenolic Contents and Antioxidant Characteristics of Microwave Assisted Extracts of Watermelon Rind Powder Microwave Assisted Extracts of Watermelon Rind Powder

Watermelon is gaining importance as a functional food due to its therapeutic effect. The therapeutic effect of watermelon has been reported and has been attributed to antioxidant constitutes. The major component in watermelon rind is citrulline that has a strong antioxidant effect which protect body from free-radical damage. Objective: This study was conducted to investigate the effect of microwave powers (150 W, 300 W & 450 W) and time intervals (1, 3 & 5 minutes) on total phenolic content (TPC) and total flavonoid content (TFC) and antioxidant characteristics i.e. DPPH and ferric reducing antioxidant potential (FRAP) of microwave assisted extracts of watermelon rind powder. Methods: The extracts collected after Microwave assisted extraction (MAE) of watermelon rind wereanalyzed for their antioxidant potential through different tests including total phenolic contents (TPC), total flavonoid content (TFC), DPPH assayand FRAP. Results: Microwave assisted extraction by using ethanol as a solvent at different microwave powers and various time intervals showed that total antioxidant potential was significantly higher at low microwave power such as TPC ranges obtained at 150W for 1, 3 & 5 minutes of time intervals show ranges (159.84, 160.04 & 169.71 mg GAE/100 g). While TFC ranges at 150W for time 1, 3 & 5 minutes were (21.31, 24.15 & 42.20 mg CEQ/100g) whereas DPPH ranges at 150W for time 1, 3 & 5 minutes were (53.14, 54.87 & 68.17 % ascorbic acid inhibition) and FRAP values at 150W for time 1, 3 & 5 minutes were (201.71, 221.50 & 326.43 mg FE/100g). While high microwave power 450W can result in disruption of some antioxidants at various time intervals. Conclusions: Watermelon rind is a rich source of many antioxidants andmicrowave assisted extraction technique should be implemented in the food and nutraceutical industries and microwave assisted extracts of watermelon rind should be utilize for the development of new functional food to combat many health related problems

A Gis Based Impact Assessment of Urbanization on Eco-System Services in Islamabad & Rawalpindi

The challenges accompanying socio-ecological and demographic transformations in the urban areas necessitate for coordinated efforts to ensure urban ecological resilience. Trans-disciplinary analytical construct of urban eco-system services (UES) empowers the policy makers and urban planners to synchronize the orientations of human impacts and resilience of ecological resources in urban areas. The current study provides a systematic overview about the research orientations, approaches and techniques used in the recent studies regarding UES. The study examined: what types of evaluation methods were adopted in the recent UES research? What is their spatial and temporal pattern? What types of UES were focused and environmental components relied upon for the assessment? To address these questions, 116 relevant publications were scrutinized by using a set of assessment criteria. The findings indicated a lesser focus in research towards UES in developing countries as compared to the volume and increasing share of their urban population. The study also establishes that an overwhelming proportion of the UES research was carried out in the industrialized countries of the northern hemisphere but rather skewed towards studying regulatory eco-system services. The recommendations for improving the relevancy of contemporary research for stakeholders were made. The present study deciphers the impacts of urban planning and role of socio-economic determinants on the perception about urban vegetation. The residents inhabiting the planned (Islamabad) and the semi-planned (Rawalpindi) urban centres were the study population. Both urban areas, lying in close proximity, face rapid transformations in LULC due to urbanization. Despite their closeness, such variants as discrepancies in the standards of urban-planning and socio-economic characteristics of inhabitants make them apt study-sites. The inhabitants’ perception was tapped regarding the importance of urban vegetation, temporal and spatial changes and their impacts. The majority concurred to its efficacy, a substantial proportion observed transformations in it over time while a reasonable number perceived these changes as negative and unwelcome. Such socio-economic determinants as location, education, gender, ownership status of residence and income of respondents were studied, deploying Statistical analyses (KW). Responses varied, with location and income weighing-in more heavily. Pairwise comparison (WRST) further vindicated the results. Urbanization is sure to tarnish the environmental sustainability of both cities. Synchronized efforts from all stakeholders are a must. LULC changes transform everything. They test the resilience of natural environment making their study imperative.Such advanced tools as remote sensing (RS) and geographic information system (GIS) were deployed and assessments made by developing codes in the Google earth engine (GEE). The current investigation used Islamabad and Rawalpindi as contextual settings. These physically close cities are distanced by contradictory policies and management frameworks rendering them as perfect locales for research. Temporal quantitative fluctuations in the selected LULC were observed and shrinkages and expansions noticed according to the varying human needs. Population-growth and migration have, primarily, triggered these transformations. The intrusion of private conglomerates for their business gains, made urbanization unruly.The study reveals how organized land-management policies succeeded in Islamabad and compromised policies failed in Rawalpindi. Effective legislation and compelling implementation are indispensable for sustained urban growth. Urbanization is proving stressful for the supply-demand budget of eco-system Services (ESS) and a real challenge of the present times. It is accelerating in Pakistan and demands enhanced focus on ESS research. Keeping in view the contextual constraints, the land cover-based Matrix Model was relied upon. It linked the LULC types of the study area for assessments of supply and demand potential of ESS by integrating expertbased judgments. The findings established that the built up areas are the principal consumer and ecological resources as producers of ESS in the study context. The degeneration in the performances of ecological infrastructure is more acute in Rawalpindi as compared to Islamabad. The observed variations are rooted in the differences in the socio-demographic aspects planning and management.The findings confirmed that the matrix model is a pragmatic option for assessing the supply-demand potentials of ESS in developing regions.