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Thesis Chapters by Jalal Barkhordari

The 2ndWASWAC World Conference THE THREATS TO LAND AND WATER RESOURCES IN THE 21STCENTURY: PREVENTION, MITIGATION AND RESTORATION, 2013

Inappropriate use of soil and water resources may result in a variety of socio-economic problems.... more Inappropriate use of soil and water resources may result in a variety of socio-economic problems. These lands are defined as water-short, controlling of this enormous flow, and managing to use beneficially, would change wastelands into verdant sceneries. In spite of crops, range plants and trees irrigated by floods increases production by many folds, the presence of potential aquifers in water-short areas completes the picture. Aquifers which may be recharged by flood water and yield significant quantities of fresh water to wells, Qanats and spring. Considering the extent and depth of course-grained alluvia, astronomical volume of water can be stored in them, as least 500 km3 in Iran. Therefore, flood water has to be controlled and used not only for diminishing damages caused by the floods but also for flood irrigation and store in aquifers for gradual utilization.
The floodwater spreading project started in 1990, using the flood water of the Azam River. About 1600 ha of the desert were brought under operation during the 1990 -2010 period. Khoushk, Fath Abad, Ali Abad and Heart villages have received the most benefits from the project. Following necessary information by filling out 69 questionnaires by peasants and governmental official at random, was obtained in the four villages: areas of rain-fed and irrigated land farmed by each household, unit price of agricultural commodities, total expenses of agricultural production, the mean yield of each crop in the study area, number of households in a village, number of livestock owned by a household, annual income and expense of each household, number of wells in a village the mean area irrigated by a single well, number of family members, occupation of the family members, number of migrants. The benefit-cost ratio method was used in finding the economic return of the project. To find out whether the artificial recharge of groundwater caused an increase in the number of wells, 3 villages outside of the influence of the project were selected as controls and the trend in well digging was studied.

The 2ndWASWAC World Conference THE THREATS TO LAND AND WATER RESOURCES IN THE 21STCENTURY:PREVENTION, MITIGATION AND RESTORATION, 2013

Water is one of the important basements in the agricultural production. Shortages of water qualit... more Water is one of the important basements in the agricultural production. Shortages of water quality and quantities from the ancient in the kavir area of Yazd province caused utility of specific management method to increase profitability of irrigation .less-irrigation is one of the methods which has been used from the ancient. In this management method, it's tried to maximize the profitability of pure profit due to unit volume of water, considering conditions and effective elements. Biography of agricultural activities in Yazd province shows that less-irrigation method was used for the old times in surface irrigation. This method mainly include providing the best planting pattern and agricultural activities such as vegetation density , fallow and alternation for using precipitation and storing humidity, changing plant time to shorten growth period, planting resistant and tolerable plants to drought. The quality of using this method in different parts of Yazd were studied. In Abarkooh to keep and preserve pistachio gardens, farmers take the latest water of wheat and irrigate pistachios. In Sadoogh to plant summer crops farmer use the latest water of wheat or barely. Investigation showed that using this method may increase profitability and exceeding valuation of whole agricultural productions. Because agricultural mixed of different activities. INTRODUCTION: Due to dry and ultra dry climate in Yazd province and little precipitation (mean annual about 105 mm) agricultural activities are difficult .Ground waters resources are the only resources which used for agricultural production. Despite of extended area of province which include 4.5% of whole country but agricultural lands are only 0.74%. This percentage of agricultural lands is based on utility of dry land agricultural methods using less irrigation and Qantas water. Basically less irrigation is a technique for irrigated vegetations (Faryab) to use maximum profit of water volume unit and maximum benefit of land unit to obtain maximum pure benefit. Shortage of water resources in agricultural section of province caused extension of using this method before drilling deep wells and 3000 Qantas are constructed. This article is based on investigation as: Collection and record of native knowledge in agricultural section in Yazd province during 1382-1383(2003-2004) In this study historical resources around water and irrigation water used .In addition ,field study has been done anal , query forms was filled by qualified farmers and experts .Analysis of data and information fulfilled by SPSS software.

Iranian Journal of Range and Desert Research, 2015

In this research, the long-term monthly water balance of Yazd-Ardakan watershed, with an area 160... more In this research, the long-term monthly water balance of Yazd-Ardakan watershed, with
an area 16000 km2, was developed based on Thornthwaite–Mather method in GIS.
Model input data included the monthly maps of temperature, precipitation, and soil
water holding capacity in roots with a cell size of 60 m, and model output included
monthly maps of actual evapotranspiration, map of soil water storage, the lack of
moisture and excess water, determined by Ilwis software. Results showed that more
than 80% of rainfall exited the watershed as evapotranspiration, approximately 8% as
surface runoff, and the rest as subsurface runoff in the study area. The amount and area
of groundwater recharges varied between 20-50% in different months.Groundwater
recharge occurred only in December to March, whose value varied between .5 mm in
December to 17 mm in January

The University of Twente, ITC, 2003

Watershed analysis provides a framework for ecosystem management, which is currently the best opt... more Watershed analysis provides a framework for ecosystem management, which is currently the best option for conservation and management of natural resources. The water cycle regulates and reflects the natural variability of the physical processes which impact on ecosystems. Considering the constraints associated with presently available techniques for evaluating land use impacts on the water cycle, such as paired catchment method and modelling (Elkaduwa, 1998), this study provides an alternative approach to ascertain the actual changes in hydrologic response of a particular watershed to land use transfor-mations made in the past. The alternative rapid approach, as applied here to the Minab catchment (ca. 1.106 ha) in the South of Iran, includes the analysis of long-term historical time series of data on rainfall, land use and streamflow, to discern changes in the water-shed and their effects on the hydrologic regime. The analysis also takes into account the hydrologically relevant changes and effects at the landscape level, as a guide to identify appropriate options for land and water management. Such management practises largely depend on the degree of variation in the hydrologic response of the watershed to recent land use changes (1975-2000). Therefore, this research project intends to map land use (e.g. overgrazing and deforestation) changes by means of satellite remote sensing and to assess the effect of land use changes on the hydrologic regime (high flow and low flow) of the Minab catchment.
In 1976, about 45 percent of the watershed area was covered by rangeland and natural forest (referred to as medium rangeland, good rangeland and forest). Due to continued overgrazing, rangeland cover decreased to 10 percent in 1988 and to 8 percent in 2002. During a period of ca. 25 years, three main land use classes at a large scale have replaced these fertile rangelands. These are characterized by: poor natural cover (e.g. poor range-land, bare soil and rock out crop), agriculture area (e.g. irrigated agriculture, rainfed agri-culture and orchard) and residential area. This destruction of natural vegetation covers have resulted in a decrease in the annual total water yield by 3.4 mm, with a decrease in the base flow during the low-flow period (May-November) and an increase in the storm runoff during the high-flow period (December to April). Also, the evaluation of flow du-ration curves shows a reduction in flow duration in the 1984-1990 and 1991-2000 peri-ods in comparison with the 1975-1983 period. Flow duration during 1984-1990 is more related to climate change. However, regarding to the increasing annual rainfall in 1991-2000, the flow duration of the river has been reduced. This is related to the shortening of the low flow period of the river. That is the reason why the percentages of low and me-dium discharges have decreased. It can be concluded that most of the runoff is discharged from the catchment by floods that take place during high flow periods. The results also show that average base flow discharge, during low flow periods, decreased.

It can be concluded that climatic variability and land use change are the most important factors affecting the (changes in the) hydrologic regime of the Minab catchment. For a return period of more than 10 years, (high) rainfall intensity as a climatic factor is consid-ered dominant. Other factors such as land use change are considered less important then. For a return period of less than 10 years and in combination with a low flow period, land use change is clearly the dominant factor determining the flow regime. Therefore, an ac-tive management strategy aimed at the conservation and regeneration of the natural vege-tation is recommended, in order to improve the distribution of water throughout the entire Minab catchment, during both dry and wet periods.

Watershed Management Research (Pajouhesh & Sazandegi)

Fresh water is becoming a scarce resource of the arid region. The only option left to manage with... more Fresh water is becoming a scarce resource of the arid region. The only option left to manage with this situation
is to conserve water resources. Since the amount of rainfall and evapotranspiration rate vary within a watershed,
available water for surface and groundwater recharge also varies both on spatial and temporal scales. Moreover,
groundwater recharge (and ultimately the total water yield) is directly influenced by the soil texture and land cover
in the watershed.
In this study, the distributed Thornthwaite-Mather water balance model for the Yazd- Ardakan catchment in Iran
was developed based on monthly precipitation, potential evapotranspiration maps and water holding capacity map.
The amount of annual runoff from the catchment predicted by the model is 66.7 mm , which is accumulated in the
plain and then salt desert. Half of discharge is contributed by the direct runoff and the groundwater contribution is
significant.
A statistical comparison of the estimated and the measured stream flow of Pishkouh show the mean monthly and
mean annual estimated and measured stream flows, the correlation coefficient between measured and estimated
stream flows, the mean monthly and annual percentage error of estimation and the 90% confidence interval for the
mean stream flow. Since the study of water balance using the TM method with the help of remote sensing and GIS
was found to be very helpful in determining the amount of monthly runoff in an arid region like the Yazd-Ardakan
catchment.

Papers by Jalal Barkhordari

Groundwater for Sustainable Development

2017 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC), 2017

Transition metal dichalcogenides are a novel class of materials which seems almost ideal to study... more Transition metal dichalcogenides are a novel class of materials which seems almost ideal to study light-matter coupling in solid state. The high thermal stability and large oscillator strength of excitons in monolayers of transition metal dichalcogenides make them ideal candidates for room temperature polaritonics. Recently, photoluminescence emission in the strong coupling regime was reported for a MoSe2 monolayer at 4 K [1]. In this talk, we discuss light-matter coupling phenomena with various kind of atomic monolayers, including WSe2, WS2 and MoSe2, which are embedded in dielectric-metal-based photonic structures. While strong coupling phenoma can be observed at cryogenic temperatures with MoSe2 monolayers, the normal mode couping regime is accessible with WSe2 and WS2 monolayers at ambient conditions.

We present a theoretical model of a driven-dissipative spin-orbit coupled Bose-Einstein condensat... more We present a theoretical model of a driven-dissipative spin-orbit coupled Bose-Einstein condensate of indirect excitons in semiconductor quantum wells (QW’s). Our steady-state solution of the problem shares analogies with the Hanle effect in an optical orientation experiment. The role of the spin pump in our case is played by boson stimulated scattering into the linearly-polarized ground state and the depolarization occurs as a result of exchange interaction between electrons and holes. Our theory agrees with the recent experiment [A. A. High et al., Phys. Rev. Lett. 110, 246403 (2013)], where spontaneous emergence of spatial coherence and polarization textures have been observed. As a complementary test, we discuss a configuration where an external magnetic field is applied in the structure plane.

We present a theoretical model of a driven-dissipative spin-orbit coupled Bose-Einstein condensat... more We present a theoretical model of a driven-dissipative spin-orbit coupled Bose-Einstein condensate of indirect excitons in semiconductor quantum wells (QW’s). Our steady-state solution of the problem shares analogies with the Hanle effect in an optical orientation experiment. The role of the spin pump in our case is played by boson stimulated scattering into the linearly-polarized ground state and the depolarization occurs as a result of exchange interaction between electrons and holes. Our theory agrees with the recent experiment [A. A. High et al., Phys. Rev. Lett. 110, 246403 (2013)], where spontaneous emergence of spatial coherence and polarization textures have been observed. As a complementary test, we discuss a configuration where an external magnetic field is applied in the structure plane.

We study the thermalization of polaritons in a semiconductor microcavity with a ring geometry abo... more We study the thermalization of polaritons in a semiconductor microcavity with a ring geometry above the condensation threshold. The lifetime of the polaritons is greater than the equilibration time for the system at cryogenic temperature (below 10 K), allowing the polariton condensate to come to thermal equilibrium. In the presence of a transverse electric and transverse magnetic splitting and a unidirectional cavity gradient (artificial gravity) in the ring, interesting polarization states emerge. We directly image the motion of the condensate in the ring using time-resolved optical microscopy techniques along with polarization resolution. The condensate is found to oscillate about the potential minimum, just like a rigid pendulum. The analogy to the rigid pendulum is verified by checking the dependence of the time period of the oscillations on the radius of the ring. Polarization dynamics provide an understanding of the interplay between the spin-orbit coupling, cavity tilt and energy dissipation which is behind the spatiotemporal polarization pattern formation in the ring.

Physical Review B, 2021

The usual concepts of topological physics, such as the Berry curvature, cannot be applied directl... more The usual concepts of topological physics, such as the Berry curvature, cannot be applied directly to non-Hermitian systems. We show that another object, the quantum metric, which often plays a secondary role in Hermitian systems, becomes a crucial quantity near exceptional points in non-Hermitian systems, where it diverges in a way that fully controls the description of wavepacket trajectories. The quantum metric behaviour is responsible for a constant acceleration with a fixed direction, and for a non-vanishing constant velocity with a controllable direction. Both contributions are independent of the wavepacket size.

Physical Review B, 2019

We theoretically study the spontaneous formation of the quantum anomalous Hall effect in a graphe... more We theoretically study the spontaneous formation of the quantum anomalous Hall effect in a graphene system of spin-bifurcated exciton-polariton condensates under nonresonant pumping. We demonstrate that, depending on the parameters of the structure, such as intensity of the pump and coupling strength between condensates, the system shows rich variety of macroscopic magnetic ordering, including analogs of ferromagnetic, antiferromagnetic, and resonant valence bond phases. Transitions between these magnetic polarized phases are associated with dramatic reshaping of the spectrum of the system connected with spontaneous appearance of topological order.

Physical Review B, 2016

We report on the unusual and counter-intuitive behaviour of spin lifetime of excitons in coupled ... more We report on the unusual and counter-intuitive behaviour of spin lifetime of excitons in coupled semiconductor quantum wells (CQWs) in the presence of in-plane magnetic field. Instead of conventional acceleration of spin relaxation due to the Larmor precession of electron and hole spins we observe a strong increase of the spin relaxation time at low magnetic fields followed by saturation and decrease at higher fields. We argue that this non-monotonic spin relaxation dynamics is a fingerprint of the magnetic quantum confined Stark effect. In the presence of electric field along the CQW growth axis, an applied magnetic field efficiently suppresses the exciton spin coherence, due to inhomogeneous broadening of the g-factor distribution.

Superlattices and Microstructures, 2015

continued the series of PLMCN conferences, organized annually since the year 2000, and attracted ... more continued the series of PLMCN conferences, organized annually since the year 2000, and attracted more than one hundred of participants from 25 countries. It covered a wide range of topics such as excitons, including spatially indirect, exciton-polaritons in microcavities of various kinds, spin and topological effects in excitonic condensates, single and entangled photon emitters, THz antennas, novel materials for applied purposes and fundamental research. New exciting ideas, such as polariton topological insulators, were proclaimed. Overall, the conference gathered the authors of recent works significantly contributing to the advance of the light-matter coupling physics. It has been for the first time demostrated by Sigurdsson et al. [1] that the ability of circularly polarized light to break the time-reversal symmetry may be witnessed in an analog of Aharonov-Bohm effect, stemming from the coupling of electronic motion to electromagnetic waves. Classical Aharonov-Bohm effect was also profoundly studied by Suaza et al. [2] in quantum ribbons with a neutral donor situated inside.

Superlattices and Microstructures, 2016

Environmental Earth Sciences, 2016

Drought is an insidious hazard of nature. It is often referred to as a ''creeping phenomenon,'' a... more Drought is an insidious hazard of nature. It is often referred to as a ''creeping phenomenon,'' and its impacts vary from region to region. Studies show that the best approach to managing drought is to apply a comprehensive drought management plan. This system necessitates collecting reliable information to make decisions to decrease the risk and damages caused by drought. Therefore, the first step of the comprehensive drought management is accomplished by preparation of the drought vulnerability map. The main object of this study was to provide for agriculture drought vulnerability mapping for Taft town located in Yazd Province, Iran. To do so, with regard to factors affecting on agricultural drought, maps were prepared for each factor and analytic hierarchy process technique was applied to determine the importance of each map as an input parameter on agricultural drought vulnerability. All input maps and the output of this research, an agricultural drought vulnerability map, were provided and analyzed by geographic information systems. Then, to evaluate and validate how accurately the vulnerability map shows the degree of proneness to agricultural droughts, some ground control points (GCP) were taken into consideration. Results indicated that there is a good agreement between agricultural drought vulnerability map and GCPs in many cases. Also, results showed that mountainous regions of the study area are more vulnerable to agriculture droughts compared with plains. These results can be helpful for decision makers to mitigate agricultural drought impacts over the region, although implementing a drought risk management plan requires a detailed study covering different aspects of drought.

Nature communications, 2015

Layered materials can be assembled vertically to fabricate a new class of van der Waals heterostr... more Layered materials can be assembled vertically to fabricate a new class of van der Waals heterostructures a few atomic layers thick, compatible with a wide range of substrates and optoelectronic device geometries, enabling new strategies for control of light-matter coupling. Here, we incorporate molybdenum diselenide/hexagonal boron nitride (MoSe2/hBN) quantum wells in a tunable optical microcavity. Part-light-part-matter polariton eigenstates are observed as a result of the strong coupling between MoSe2 excitons and cavity photons, evidenced from a clear anticrossing between the neutral exciton and the cavity modes with a splitting of 20 meV for a single MoSe2 monolayer, enhanced to 29 meV in MoSe2/hBN/MoSe2 double-quantum wells. The splitting at resonance provides an estimate of the exciton radiative lifetime of 0.4 ps. Our results pave the way for room-temperature polaritonic devices based on multiple-quantum-well van der Waals heterostructures, where polariton condensation and el...

The 2ndWASWAC World Conference THE THREATS TO LAND AND WATER RESOURCES IN THE 21STCENTURY: PREVENTION, MITIGATION AND RESTORATION, 2013

Inappropriate use of soil and water resources may result in a variety of socio-economic problems.... more Inappropriate use of soil and water resources may result in a variety of socio-economic problems. These lands are defined as water-short, controlling of this enormous flow, and managing to use beneficially, would change wastelands into verdant sceneries. In spite of crops, range plants and trees irrigated by floods increases production by many folds, the presence of potential aquifers in water-short areas completes the picture. Aquifers which may be recharged by flood water and yield significant quantities of fresh water to wells, Qanats and spring. Considering the extent and depth of course-grained alluvia, astronomical volume of water can be stored in them, as least 500 km3 in Iran. Therefore, flood water has to be controlled and used not only for diminishing damages caused by the floods but also for flood irrigation and store in aquifers for gradual utilization.
The floodwater spreading project started in 1990, using the flood water of the Azam River. About 1600 ha of the desert were brought under operation during the 1990 -2010 period. Khoushk, Fath Abad, Ali Abad and Heart villages have received the most benefits from the project. Following necessary information by filling out 69 questionnaires by peasants and governmental official at random, was obtained in the four villages: areas of rain-fed and irrigated land farmed by each household, unit price of agricultural commodities, total expenses of agricultural production, the mean yield of each crop in the study area, number of households in a village, number of livestock owned by a household, annual income and expense of each household, number of wells in a village the mean area irrigated by a single well, number of family members, occupation of the family members, number of migrants. The benefit-cost ratio method was used in finding the economic return of the project. To find out whether the artificial recharge of groundwater caused an increase in the number of wells, 3 villages outside of the influence of the project were selected as controls and the trend in well digging was studied.

The 2ndWASWAC World Conference THE THREATS TO LAND AND WATER RESOURCES IN THE 21STCENTURY:PREVENTION, MITIGATION AND RESTORATION, 2013

Water is one of the important basements in the agricultural production. Shortages of water qualit... more Water is one of the important basements in the agricultural production. Shortages of water quality and quantities from the ancient in the kavir area of Yazd province caused utility of specific management method to increase profitability of irrigation .less-irrigation is one of the methods which has been used from the ancient. In this management method, it's tried to maximize the profitability of pure profit due to unit volume of water, considering conditions and effective elements. Biography of agricultural activities in Yazd province shows that less-irrigation method was used for the old times in surface irrigation. This method mainly include providing the best planting pattern and agricultural activities such as vegetation density , fallow and alternation for using precipitation and storing humidity, changing plant time to shorten growth period, planting resistant and tolerable plants to drought. The quality of using this method in different parts of Yazd were studied. In Abarkooh to keep and preserve pistachio gardens, farmers take the latest water of wheat and irrigate pistachios. In Sadoogh to plant summer crops farmer use the latest water of wheat or barely. Investigation showed that using this method may increase profitability and exceeding valuation of whole agricultural productions. Because agricultural mixed of different activities. INTRODUCTION: Due to dry and ultra dry climate in Yazd province and little precipitation (mean annual about 105 mm) agricultural activities are difficult .Ground waters resources are the only resources which used for agricultural production. Despite of extended area of province which include 4.5% of whole country but agricultural lands are only 0.74%. This percentage of agricultural lands is based on utility of dry land agricultural methods using less irrigation and Qantas water. Basically less irrigation is a technique for irrigated vegetations (Faryab) to use maximum profit of water volume unit and maximum benefit of land unit to obtain maximum pure benefit. Shortage of water resources in agricultural section of province caused extension of using this method before drilling deep wells and 3000 Qantas are constructed. This article is based on investigation as: Collection and record of native knowledge in agricultural section in Yazd province during 1382-1383(2003-2004) In this study historical resources around water and irrigation water used .In addition ,field study has been done anal , query forms was filled by qualified farmers and experts .Analysis of data and information fulfilled by SPSS software.

Iranian Journal of Range and Desert Research, 2015

In this research, the long-term monthly water balance of Yazd-Ardakan watershed, with an area 160... more In this research, the long-term monthly water balance of Yazd-Ardakan watershed, with
an area 16000 km2, was developed based on Thornthwaite–Mather method in GIS.
Model input data included the monthly maps of temperature, precipitation, and soil
water holding capacity in roots with a cell size of 60 m, and model output included
monthly maps of actual evapotranspiration, map of soil water storage, the lack of
moisture and excess water, determined by Ilwis software. Results showed that more
than 80% of rainfall exited the watershed as evapotranspiration, approximately 8% as
surface runoff, and the rest as subsurface runoff in the study area. The amount and area
of groundwater recharges varied between 20-50% in different months.Groundwater
recharge occurred only in December to March, whose value varied between .5 mm in
December to 17 mm in January

The University of Twente, ITC, 2003

Watershed analysis provides a framework for ecosystem management, which is currently the best opt... more Watershed analysis provides a framework for ecosystem management, which is currently the best option for conservation and management of natural resources. The water cycle regulates and reflects the natural variability of the physical processes which impact on ecosystems. Considering the constraints associated with presently available techniques for evaluating land use impacts on the water cycle, such as paired catchment method and modelling (Elkaduwa, 1998), this study provides an alternative approach to ascertain the actual changes in hydrologic response of a particular watershed to land use transfor-mations made in the past. The alternative rapid approach, as applied here to the Minab catchment (ca. 1.106 ha) in the South of Iran, includes the analysis of long-term historical time series of data on rainfall, land use and streamflow, to discern changes in the water-shed and their effects on the hydrologic regime. The analysis also takes into account the hydrologically relevant changes and effects at the landscape level, as a guide to identify appropriate options for land and water management. Such management practises largely depend on the degree of variation in the hydrologic response of the watershed to recent land use changes (1975-2000). Therefore, this research project intends to map land use (e.g. overgrazing and deforestation) changes by means of satellite remote sensing and to assess the effect of land use changes on the hydrologic regime (high flow and low flow) of the Minab catchment.
In 1976, about 45 percent of the watershed area was covered by rangeland and natural forest (referred to as medium rangeland, good rangeland and forest). Due to continued overgrazing, rangeland cover decreased to 10 percent in 1988 and to 8 percent in 2002. During a period of ca. 25 years, three main land use classes at a large scale have replaced these fertile rangelands. These are characterized by: poor natural cover (e.g. poor range-land, bare soil and rock out crop), agriculture area (e.g. irrigated agriculture, rainfed agri-culture and orchard) and residential area. This destruction of natural vegetation covers have resulted in a decrease in the annual total water yield by 3.4 mm, with a decrease in the base flow during the low-flow period (May-November) and an increase in the storm runoff during the high-flow period (December to April). Also, the evaluation of flow du-ration curves shows a reduction in flow duration in the 1984-1990 and 1991-2000 peri-ods in comparison with the 1975-1983 period. Flow duration during 1984-1990 is more related to climate change. However, regarding to the increasing annual rainfall in 1991-2000, the flow duration of the river has been reduced. This is related to the shortening of the low flow period of the river. That is the reason why the percentages of low and me-dium discharges have decreased. It can be concluded that most of the runoff is discharged from the catchment by floods that take place during high flow periods. The results also show that average base flow discharge, during low flow periods, decreased.

It can be concluded that climatic variability and land use change are the most important factors affecting the (changes in the) hydrologic regime of the Minab catchment. For a return period of more than 10 years, (high) rainfall intensity as a climatic factor is consid-ered dominant. Other factors such as land use change are considered less important then. For a return period of less than 10 years and in combination with a low flow period, land use change is clearly the dominant factor determining the flow regime. Therefore, an ac-tive management strategy aimed at the conservation and regeneration of the natural vege-tation is recommended, in order to improve the distribution of water throughout the entire Minab catchment, during both dry and wet periods.

Watershed Management Research (Pajouhesh & Sazandegi)

Fresh water is becoming a scarce resource of the arid region. The only option left to manage with... more Fresh water is becoming a scarce resource of the arid region. The only option left to manage with this situation
is to conserve water resources. Since the amount of rainfall and evapotranspiration rate vary within a watershed,
available water for surface and groundwater recharge also varies both on spatial and temporal scales. Moreover,
groundwater recharge (and ultimately the total water yield) is directly influenced by the soil texture and land cover
in the watershed.
In this study, the distributed Thornthwaite-Mather water balance model for the Yazd- Ardakan catchment in Iran
was developed based on monthly precipitation, potential evapotranspiration maps and water holding capacity map.
The amount of annual runoff from the catchment predicted by the model is 66.7 mm , which is accumulated in the
plain and then salt desert. Half of discharge is contributed by the direct runoff and the groundwater contribution is
significant.
A statistical comparison of the estimated and the measured stream flow of Pishkouh show the mean monthly and
mean annual estimated and measured stream flows, the correlation coefficient between measured and estimated
stream flows, the mean monthly and annual percentage error of estimation and the 90% confidence interval for the
mean stream flow. Since the study of water balance using the TM method with the help of remote sensing and GIS
was found to be very helpful in determining the amount of monthly runoff in an arid region like the Yazd-Ardakan
catchment.

Groundwater for Sustainable Development

2017 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC), 2017

Transition metal dichalcogenides are a novel class of materials which seems almost ideal to study... more Transition metal dichalcogenides are a novel class of materials which seems almost ideal to study light-matter coupling in solid state. The high thermal stability and large oscillator strength of excitons in monolayers of transition metal dichalcogenides make them ideal candidates for room temperature polaritonics. Recently, photoluminescence emission in the strong coupling regime was reported for a MoSe2 monolayer at 4 K [1]. In this talk, we discuss light-matter coupling phenomena with various kind of atomic monolayers, including WSe2, WS2 and MoSe2, which are embedded in dielectric-metal-based photonic structures. While strong coupling phenoma can be observed at cryogenic temperatures with MoSe2 monolayers, the normal mode couping regime is accessible with WSe2 and WS2 monolayers at ambient conditions.

We present a theoretical model of a driven-dissipative spin-orbit coupled Bose-Einstein condensat... more We present a theoretical model of a driven-dissipative spin-orbit coupled Bose-Einstein condensate of indirect excitons in semiconductor quantum wells (QW’s). Our steady-state solution of the problem shares analogies with the Hanle effect in an optical orientation experiment. The role of the spin pump in our case is played by boson stimulated scattering into the linearly-polarized ground state and the depolarization occurs as a result of exchange interaction between electrons and holes. Our theory agrees with the recent experiment [A. A. High et al., Phys. Rev. Lett. 110, 246403 (2013)], where spontaneous emergence of spatial coherence and polarization textures have been observed. As a complementary test, we discuss a configuration where an external magnetic field is applied in the structure plane.

We present a theoretical model of a driven-dissipative spin-orbit coupled Bose-Einstein condensat... more We present a theoretical model of a driven-dissipative spin-orbit coupled Bose-Einstein condensate of indirect excitons in semiconductor quantum wells (QW’s). Our steady-state solution of the problem shares analogies with the Hanle effect in an optical orientation experiment. The role of the spin pump in our case is played by boson stimulated scattering into the linearly-polarized ground state and the depolarization occurs as a result of exchange interaction between electrons and holes. Our theory agrees with the recent experiment [A. A. High et al., Phys. Rev. Lett. 110, 246403 (2013)], where spontaneous emergence of spatial coherence and polarization textures have been observed. As a complementary test, we discuss a configuration where an external magnetic field is applied in the structure plane.

We study the thermalization of polaritons in a semiconductor microcavity with a ring geometry abo... more We study the thermalization of polaritons in a semiconductor microcavity with a ring geometry above the condensation threshold. The lifetime of the polaritons is greater than the equilibration time for the system at cryogenic temperature (below 10 K), allowing the polariton condensate to come to thermal equilibrium. In the presence of a transverse electric and transverse magnetic splitting and a unidirectional cavity gradient (artificial gravity) in the ring, interesting polarization states emerge. We directly image the motion of the condensate in the ring using time-resolved optical microscopy techniques along with polarization resolution. The condensate is found to oscillate about the potential minimum, just like a rigid pendulum. The analogy to the rigid pendulum is verified by checking the dependence of the time period of the oscillations on the radius of the ring. Polarization dynamics provide an understanding of the interplay between the spin-orbit coupling, cavity tilt and energy dissipation which is behind the spatiotemporal polarization pattern formation in the ring.

Physical Review B, 2021

The usual concepts of topological physics, such as the Berry curvature, cannot be applied directl... more The usual concepts of topological physics, such as the Berry curvature, cannot be applied directly to non-Hermitian systems. We show that another object, the quantum metric, which often plays a secondary role in Hermitian systems, becomes a crucial quantity near exceptional points in non-Hermitian systems, where it diverges in a way that fully controls the description of wavepacket trajectories. The quantum metric behaviour is responsible for a constant acceleration with a fixed direction, and for a non-vanishing constant velocity with a controllable direction. Both contributions are independent of the wavepacket size.

Physical Review B, 2019

We theoretically study the spontaneous formation of the quantum anomalous Hall effect in a graphe... more We theoretically study the spontaneous formation of the quantum anomalous Hall effect in a graphene system of spin-bifurcated exciton-polariton condensates under nonresonant pumping. We demonstrate that, depending on the parameters of the structure, such as intensity of the pump and coupling strength between condensates, the system shows rich variety of macroscopic magnetic ordering, including analogs of ferromagnetic, antiferromagnetic, and resonant valence bond phases. Transitions between these magnetic polarized phases are associated with dramatic reshaping of the spectrum of the system connected with spontaneous appearance of topological order.

Physical Review B, 2016

We report on the unusual and counter-intuitive behaviour of spin lifetime of excitons in coupled ... more We report on the unusual and counter-intuitive behaviour of spin lifetime of excitons in coupled semiconductor quantum wells (CQWs) in the presence of in-plane magnetic field. Instead of conventional acceleration of spin relaxation due to the Larmor precession of electron and hole spins we observe a strong increase of the spin relaxation time at low magnetic fields followed by saturation and decrease at higher fields. We argue that this non-monotonic spin relaxation dynamics is a fingerprint of the magnetic quantum confined Stark effect. In the presence of electric field along the CQW growth axis, an applied magnetic field efficiently suppresses the exciton spin coherence, due to inhomogeneous broadening of the g-factor distribution.

Superlattices and Microstructures, 2015

continued the series of PLMCN conferences, organized annually since the year 2000, and attracted ... more continued the series of PLMCN conferences, organized annually since the year 2000, and attracted more than one hundred of participants from 25 countries. It covered a wide range of topics such as excitons, including spatially indirect, exciton-polaritons in microcavities of various kinds, spin and topological effects in excitonic condensates, single and entangled photon emitters, THz antennas, novel materials for applied purposes and fundamental research. New exciting ideas, such as polariton topological insulators, were proclaimed. Overall, the conference gathered the authors of recent works significantly contributing to the advance of the light-matter coupling physics. It has been for the first time demostrated by Sigurdsson et al. [1] that the ability of circularly polarized light to break the time-reversal symmetry may be witnessed in an analog of Aharonov-Bohm effect, stemming from the coupling of electronic motion to electromagnetic waves. Classical Aharonov-Bohm effect was also profoundly studied by Suaza et al. [2] in quantum ribbons with a neutral donor situated inside.

Superlattices and Microstructures, 2016

Environmental Earth Sciences, 2016

Drought is an insidious hazard of nature. It is often referred to as a ''creeping phenomenon,'' a... more Drought is an insidious hazard of nature. It is often referred to as a ''creeping phenomenon,'' and its impacts vary from region to region. Studies show that the best approach to managing drought is to apply a comprehensive drought management plan. This system necessitates collecting reliable information to make decisions to decrease the risk and damages caused by drought. Therefore, the first step of the comprehensive drought management is accomplished by preparation of the drought vulnerability map. The main object of this study was to provide for agriculture drought vulnerability mapping for Taft town located in Yazd Province, Iran. To do so, with regard to factors affecting on agricultural drought, maps were prepared for each factor and analytic hierarchy process technique was applied to determine the importance of each map as an input parameter on agricultural drought vulnerability. All input maps and the output of this research, an agricultural drought vulnerability map, were provided and analyzed by geographic information systems. Then, to evaluate and validate how accurately the vulnerability map shows the degree of proneness to agricultural droughts, some ground control points (GCP) were taken into consideration. Results indicated that there is a good agreement between agricultural drought vulnerability map and GCPs in many cases. Also, results showed that mountainous regions of the study area are more vulnerable to agriculture droughts compared with plains. These results can be helpful for decision makers to mitigate agricultural drought impacts over the region, although implementing a drought risk management plan requires a detailed study covering different aspects of drought.

Nature communications, 2015

Layered materials can be assembled vertically to fabricate a new class of van der Waals heterostr... more Layered materials can be assembled vertically to fabricate a new class of van der Waals heterostructures a few atomic layers thick, compatible with a wide range of substrates and optoelectronic device geometries, enabling new strategies for control of light-matter coupling. Here, we incorporate molybdenum diselenide/hexagonal boron nitride (MoSe2/hBN) quantum wells in a tunable optical microcavity. Part-light-part-matter polariton eigenstates are observed as a result of the strong coupling between MoSe2 excitons and cavity photons, evidenced from a clear anticrossing between the neutral exciton and the cavity modes with a splitting of 20 meV for a single MoSe2 monolayer, enhanced to 29 meV in MoSe2/hBN/MoSe2 double-quantum wells. The splitting at resonance provides an estimate of the exciton radiative lifetime of 0.4 ps. Our results pave the way for room-temperature polaritonic devices based on multiple-quantum-well van der Waals heterostructures, where polariton condensation and el...

Physical Review Letters, 2015

Recent search for optical analogues of topological phenomena mainly focuses on mimicking the key ... more Recent search for optical analogues of topological phenomena mainly focuses on mimicking the key feature of quantum Hall [1] and quantum spin Hall [2] effects (QHE and QSHE): edge currents protected from disorder. QHE relies on time-reversal symmetry breaking, which can be realised in photonic gyromagnetic crystals [3]. In the optical range, the weak magneto-optical activity may be replaced with helical design of coupled waveguides, converting light propagation into a timedependent perturbation [4]. Finally, optical QHE due to artificial gauge fields [5] was predicted in microcavity lattices. Here, we consider honeycomb arrays of microcavity pillars [6] as an alternative optical-frequency 2D topological insulator. We show that the interplay between the photonic spinorbit coupling natively present in this system [7, 8] and the Zeeman splitting of exciton-polaritons in external magnetic fields [9] leads to the opening of a non-trivial gap characterised by C = ±2 set of band Chern numbers and to the formation of topologically protected one-way edge states.

Physical Review Letters, 2013

Journal of Rangeland Science, 2012

Classifying remote sensing imageries to obtain reliable and accurate Land Use/Cover (LUC) informa... more Classifying remote sensing imageries to obtain reliable and accurate Land Use/Cover (LUC) information still remains a challenge that depends on many factors such as complexity of landscape especially in arid region. The aim of this paper is to extract reliable LUC information from Land sat imageries of the Pishkouh watershed of central arid region, Iran. The classical Maximum Likelihood Classifier (MLC) was first applied to classify Land sat image of 15 July 2007. The major LUC identified were shrubland (rangeland), agricultural land, orchard, river, settlement. Applying Post-Classification Correction (PCC) using ancillary data and knowledge-based logic rules the overall classification accuracy was improved from about 72% to 91% for LUC map. The improved overall Kappa statistics due to PCC were 0.88. The PCC maps, assessed by accuracy matrix, were found to have much higher accuracy in comparison to their counterpart MLC maps. The overall improvement in classification accuracy of the...

3th national Water resource Management of Iran, 2002

A fundamental method for ecosystem management is extensive contemplation basin. That result will ... more A fundamental method for ecosystem management is extensive contemplation basin. That result will be best management and preserve of natural resources. The goal of this research is investigation of Land cover and climate changes effects on flood probable changes in last decades. The study area is located in latitudes 26º 58' and 28º 30' N longitudes 56º 49' and 57º 52' E .In last researches have used different methods as mathematical models and double watersheds for the purpose assigning the effects of land cover and climate change on water basin cycle.
In this research is an investigated effect of land cover change on peak flood and flood volume using GIS and HEC-HMS model. Also were simulated basin hydrologic reactions in lieu of different scenarios of land cover.
After the determining of land cover in tree different date using soil hydrologic groups and related table were determined CN maps for different years. The CN average have calculated for 1976, 1988, 2002 years in this manner 74, 80 and 79.
At first, the model has calibrated by tree record even and then has simulated flood using every CN and rainfall data.
The results of comparison between land cover maps During a period of ca. 25 years showed in 1976, about 45 percent of the watershed area was covered by rangeland and natural forest. Due to continued overgrazing, rangeland cover decreased to 10 percent in 1988 and to 8 percent in 2002. Naturally, we can expect to increase the runoff and river flood as result of natural resources destruction.Just as effects of land cover changes on CN from 74 to 80 and was specified in simulated peak flood 10 percent