The Experts below are selected from a list of 57 Experts worldwide ranked by ideXlab platform
Kun Wang - One of the best experts on this subject based on the ideXlab platform.
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Potassium isotope fractionation during chemical weathering of basalts
Earth and Planetary Science Letters, 2020Co-Authors: Xiaoming Liu, Heng Chen, Kun WangAbstract:Abstract Non-traditional stable Isotopes (e.g., Li, Mg, and Si) are increasingly used as tracers for studying Earth's surface processes. The Isotopes of Potassium (K), a highly soluble and mobile element during weathering, could be a promising new tracer for continental weathering; however, the K isotopic variations in weathering profile has not been directly studied due to previous analytical difficulties. Recent high-precision measurements revealed that K Isotopes in global river waters are fractionated from the Bulk Silicate Earth (BSE) value, indicating they are influenced by chemical weathering of the crust. Isotopic fractionation during chemical weathering is one of several processes that could ultimately lead to ∼0.6‰ difference of δ 41 K between the BSE and modern seawater. In order to determine the direction and controlling factors of K isotopic fractionation during basalt weathering, especially under intense weathering conditions, we measured K isotopic compositions in two sets of bauxite developed on the Columbia River Basalts, together with fresh parental basalt and aeolian deposit samples using a recently developed high-precision method. Results show that K isotopic variations among fresh basalts and aeolian dust are limited, close to the BSE value. Extreme K depletion (>99%) and K isotopic fractionation ( δ 41 K up to 0.5 ‰) are observed in bauxite drill cores due to intense chemical weathering. The top of the weathering profiles shows less depletion in K abundances and the δ 41 K values are closer to those of the fresh basalts and aeolian dusts, likely due to addition of aeolian dust at the tops of both profiles. The weathered products are generally depleted in heavy K Isotopes, which is consistent with heavier K isotopic compositions observed in river water and seawater. The δ 41 K in bauxites displays a positive correlation with K2O contents as well as δ 7 Li, indicating the behaviors of K and Li Isotopes are comparable during chemical weathering. This study shows that K concentrations and its isotopic compositions are sensitive tracers of chemical weathering and could be good weathering proxies over Earth's history.
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Potassium isotopic evidence for a high-energy giant impact origin of the Moon
Nature, 2016Co-Authors: Kun Wang, Stein B. JacobsenAbstract:Kun Wang and Stein Jacobsen report high-precision Potassium isotope data for the Earth, the Moon and chondritic meteorites, and show that lunar rocks are significantly enriched in the heavy Isotopes of Potassium compared to the Earth and chondrites. They conclude that this enrichment can be best explained as the result of the incomplete condensation of a silicate vapour during the Moon-forming giant impact event, at a relatively high ambient pressure. Such conditions would be consistent with the high-energy, high-angular-momentum giant impact model for the origin of the Moon. The Earth–Moon system has unique chemical and isotopic signatures compared with other planetary bodies^ 1 , 2 , 3 ; any successful model for the origin of this system therefore has to satisfy these chemical and isotopic constraints. The Moon is substantially depleted in volatile elements such as Potassium compared with the Earth and the bulk solar composition^ 4 , and it has long been thought to be the result of a catastrophic Moon-forming giant impact event^ 5 . Volatile-element-depleted bodies such as the Moon were expected to be enriched in heavy Potassium Isotopes during the loss of volatiles; however such enrichment was never found^ 6 . Here we report new high-precision Potassium isotope data for the Earth, the Moon and chondritic meteorites. We found that the lunar rocks are significantly (>2 σ ) enriched in the heavy Isotopes of Potassium compared to the Earth and chondrites (by around 0.4 parts per thousand). The enrichment of the heavy isotope of Potassium in lunar rocks compared with those of the Earth and chondrites can be best explained as the result of the incomplete condensation of a bulk silicate Earth vapour at an ambient pressure that is higher than 10 bar. We used these coupled constraints of the chemical loss and isotopic fractionation of K to compare two recent dynamic models that were used to explain the identical non-mass-dependent isotope composition of the Earth and the Moon. Our K isotope result is inconsistent with the low-energy disk equilibration model^ 7 , but supports the high-energy, high-angular-momentum giant impact model^ 8 for the origin of the Moon. High-precision Potassium isotope data can also be used as a ‘palaeo-barometer’ to reveal the physical conditions during the Moon-forming event. The Potassium isotope signature of lunar rocks supports the model of a high-energy giant impact as the origin of the Moon.
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Potassium isotopic evidence for a high energy giant impact origin of the moon
Nature, 2016Co-Authors: Kun Wang, Stein B. JacobsenAbstract:The Earth-Moon system has unique chemical and isotopic signatures compared with other planetary bodies; any successful model for the origin of this system therefore has to satisfy these chemical and isotopic constraints. The Moon is substantially depleted in volatile elements such as Potassium compared with the Earth and the bulk solar composition, and it has long been thought to be the result of a catastrophic Moon-forming giant impact event. Volatile-element-depleted bodies such as the Moon were expected to be enriched in heavy Potassium Isotopes during the loss of volatiles; however such enrichment was never found. Here we report new high-precision Potassium isotope data for the Earth, the Moon and chondritic meteorites. We found that the lunar rocks are significantly (>2σ) enriched in the heavy Isotopes of Potassium compared to the Earth and chondrites (by around 0.4 parts per thousand). The enrichment of the heavy isotope of Potassium in lunar rocks compared with those of the Earth and chondrites can be best explained as the result of the incomplete condensation of a bulk silicate Earth vapour at an ambient pressure that is higher than 10 bar. We used these coupled constraints of the chemical loss and isotopic fractionation of K to compare two recent dynamic models that were used to explain the identical non-mass-dependent isotope composition of the Earth and the Moon. Our K isotope result is inconsistent with the low-energy disk equilibration model, but supports the high-energy, high-angular-momentum giant impact model for the origin of the Moon. High-precision Potassium isotope data can also be used as a 'palaeo-barometer' to reveal the physical conditions during the Moon-forming event.
Stein B. Jacobsen - One of the best experts on this subject based on the ideXlab platform.
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Potassium isotopic evidence for a high-energy giant impact origin of the Moon
Nature, 2016Co-Authors: Kun Wang, Stein B. JacobsenAbstract:Kun Wang and Stein Jacobsen report high-precision Potassium isotope data for the Earth, the Moon and chondritic meteorites, and show that lunar rocks are significantly enriched in the heavy Isotopes of Potassium compared to the Earth and chondrites. They conclude that this enrichment can be best explained as the result of the incomplete condensation of a silicate vapour during the Moon-forming giant impact event, at a relatively high ambient pressure. Such conditions would be consistent with the high-energy, high-angular-momentum giant impact model for the origin of the Moon. The Earth–Moon system has unique chemical and isotopic signatures compared with other planetary bodies^ 1 , 2 , 3 ; any successful model for the origin of this system therefore has to satisfy these chemical and isotopic constraints. The Moon is substantially depleted in volatile elements such as Potassium compared with the Earth and the bulk solar composition^ 4 , and it has long been thought to be the result of a catastrophic Moon-forming giant impact event^ 5 . Volatile-element-depleted bodies such as the Moon were expected to be enriched in heavy Potassium Isotopes during the loss of volatiles; however such enrichment was never found^ 6 . Here we report new high-precision Potassium isotope data for the Earth, the Moon and chondritic meteorites. We found that the lunar rocks are significantly (>2 σ ) enriched in the heavy Isotopes of Potassium compared to the Earth and chondrites (by around 0.4 parts per thousand). The enrichment of the heavy isotope of Potassium in lunar rocks compared with those of the Earth and chondrites can be best explained as the result of the incomplete condensation of a bulk silicate Earth vapour at an ambient pressure that is higher than 10 bar. We used these coupled constraints of the chemical loss and isotopic fractionation of K to compare two recent dynamic models that were used to explain the identical non-mass-dependent isotope composition of the Earth and the Moon. Our K isotope result is inconsistent with the low-energy disk equilibration model^ 7 , but supports the high-energy, high-angular-momentum giant impact model^ 8 for the origin of the Moon. High-precision Potassium isotope data can also be used as a ‘palaeo-barometer’ to reveal the physical conditions during the Moon-forming event. The Potassium isotope signature of lunar rocks supports the model of a high-energy giant impact as the origin of the Moon.
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Potassium isotopic evidence for a high energy giant impact origin of the moon
Nature, 2016Co-Authors: Kun Wang, Stein B. JacobsenAbstract:The Earth-Moon system has unique chemical and isotopic signatures compared with other planetary bodies; any successful model for the origin of this system therefore has to satisfy these chemical and isotopic constraints. The Moon is substantially depleted in volatile elements such as Potassium compared with the Earth and the bulk solar composition, and it has long been thought to be the result of a catastrophic Moon-forming giant impact event. Volatile-element-depleted bodies such as the Moon were expected to be enriched in heavy Potassium Isotopes during the loss of volatiles; however such enrichment was never found. Here we report new high-precision Potassium isotope data for the Earth, the Moon and chondritic meteorites. We found that the lunar rocks are significantly (>2σ) enriched in the heavy Isotopes of Potassium compared to the Earth and chondrites (by around 0.4 parts per thousand). The enrichment of the heavy isotope of Potassium in lunar rocks compared with those of the Earth and chondrites can be best explained as the result of the incomplete condensation of a bulk silicate Earth vapour at an ambient pressure that is higher than 10 bar. We used these coupled constraints of the chemical loss and isotopic fractionation of K to compare two recent dynamic models that were used to explain the identical non-mass-dependent isotope composition of the Earth and the Moon. Our K isotope result is inconsistent with the low-energy disk equilibration model, but supports the high-energy, high-angular-momentum giant impact model for the origin of the Moon. High-precision Potassium isotope data can also be used as a 'palaeo-barometer' to reveal the physical conditions during the Moon-forming event.
César Raymundo - One of the best experts on this subject based on the ideXlab platform.
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Quantum liquid droplets in a mixture of Bose-Einstein condensates
2018Co-Authors: Cabrera Córdova, César RaymundoAbstract:In this thesis, we report on the design and construction of a quantum simulator experiment using quantum gases in Spain. This experiment exploits mixtures of the three Isotopes of Potassium, which give access in an original approach to the study of Bose-Bose or Bose-Fermi mixtures using the same experimental setup. We validate our experimental setup with the observation of a Bose-Einstein condensate (BEC) of 41K and 39K. Moreover we observe the dual Bose-Einstein condensation of 39K–41K. These results represents the first observation of BECs in Spain and give access to a novel quantum degenerate mixture in the field. Since the control of interactions in our experiment are crucial, we characterize the scattering properties of the 39K–41K mixture, and spin mixtures of 39K and 41K. In addition, using a spin mixture of 39K BEC, we report on the observation of a novel state of matter: a composite quantum liquid droplet. This dilute quantum droplet is a liquid-like cluster of ultra-cold atoms self-trapped by attractive mean-field forces and stabilized against collapse by repulsive beyond mean-field many-body effects. This system follows the original proposal where D. Petrov predicted the formation of self-bound liquid droplets in mixtures of Bose-Einstein condensates. In the first series of experiments, we have observed the formation of quantum droplets in a regime where the Bose-Bose mixture should collapse from the mean-field perspective.We directly measure the droplet size and ultra-low density via high-resolution in situ imaging, and experimentally confirm their self-bound nature.We demonstrate that the existence of these droplets is a striking manifestation of quantum fluctuations. These droplets do not exist in single-component condensates with described with contact interactions. Finally, we observe that for small atom numbers, quantum pressure dissociates the droplets and drives a liquid-to-gas transition, which we map out as a function of interaction strength. These measurements open an intriguing point of investigation: the difference existing between droplets and bright solitons. In the second series of experiments, we address it by placing the mixture in an optical waveguide, realizing a system that contains both composite bright solitons and quantum liquid droplets. In analogy to non-linear optics, the former can be seen as one-dimensional matter-wave solitons stabilized by dispersion, whereas the latter corresponds to highdimensional solitons stabilized by a higher order non-linearity. We find that depending on atom number, interaction strength and confinement, solitons and droplets can be smoothly connected or remain distinct states coexisting only in a bi-stable region. We measure their spin composition, extract their density for a broad range of parameters, and map out the boundary of the region separating solitons from droplets. Our experiments demonstrate a novel type of ultra-dilute quantum liquid, stabilized only by contact interactions. They provide an ideal platform for benchmarking complex quantum many-body theories beyond the mean-field approximation in a quantum simulation approach. Furthermore, they constitute a novel playground to explore experimentally self-bound states stabilized by unconventional higher order nonlinearities, relevant in non-linear optics.
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Quantum liquid droplets in a mixture of Bose-Einstein condensates
Universitat Politècnica de Catalunya, 2018Co-Authors: César RaymundoAbstract:In this thesis, we report on the design and construction of a quantum simulator experiment using quantum gases in Spain. This experiment exploits mixtures of the three Isotopes of Potassium, which give access in an original approach to the study of Bose-Bose or Bose-Fermi mixtures using the same experimental setup. We validate our experimental setup with the observation of a Bose-Einstein condensate (BEC) of 41K and 39K. Moreover we observe the dual Bose-Einstein condensation of 39K–41K. These results represents the first observation of BECs in Spain and give access to a novel quantum degenerate mixture in the field. Since the control of interactions in our experiment are crucial, we characterize the scattering properties of the 39K–41K mixture, and spin mixtures of 39K and 41K. In addition, using a spin mixture of 39K BEC, we report on the observation of a novel state of matter: a composite quantum liquid droplet. This dilute quantum droplet is a liquid-like cluster of ultra-cold atoms self-trapped by attractive mean-field forces and stabilized against collapse by repulsive beyond mean-field many-body effects. This system follows the original proposal where D. Petrov predicted the formation of self-bound liquid droplets in mixtures of Bose-Einstein condensates. In the first series of experiments, we have observed the formation of quantum droplets in a regime where the Bose-Bose mixture should collapse from the mean-field perspective.We directly measure the droplet size and ultra-low density via high-resolution in situ imaging, and experimentally confirm their self-bound nature.We demonstrate that the existence of these droplets is a striking manifestation of quantum fluctuations. These droplets do not exist in single-component condensates with described with contact interactions. Finally, we observe that for small atom numbers, quantum pressure dissociates the droplets and drives a liquid-to-gas transition, which we map out as a function of interaction strength. These measurements open an intriguing point of investigation: the difference existing between droplets and bright solitons. In the second series of experiments, we address it by placing the mixture in an optical waveguide, realizing a system that contains both composite bright solitons and quantum liquid droplets. In analogy to non-linear optics, the former can be seen as one-dimensional matter-wave solitons stabilized by dispersion, whereas the latter corresponds to highdimensional solitons stabilized by a higher order non-linearity. We find that depending on atom number, interaction strength and confinement, solitons and droplets can be smoothly connected or remain distinct states coexisting only in a bi-stable region. We measure their spin composition, extract their density for a broad range of parameters, and map out the boundary of the region separating solitons from droplets. Our experiments demonstrate a novel type of ultra-dilute quantum liquid, stabilized only by contact interactions. They provide an ideal platform for benchmarking complex quantum many-body theories beyond the mean-field approximation in a quantum simulation approach. Furthermore, they constitute a novel playground to explore experimentally self-bound states stabilized by unconventional higher order nonlinearities, relevant in non-linear optics.En este trabajo de tesis se reporta el diseño y la construcción de uno de los experimentos pioneros en España que permite realizar simulaciones cuánticas usando átomos ultra fríos. En este experimento se enfrían hasta alcanzar la degeneración cuántica los tres diferentes isotopos de potasio los cuales permiten, de manera particular y original, el estudio de mezclas cuánticas degeneradas de tipo Bose-Bose o Bose-Fermi. El funcionamiento del experimento es validado por medio de la producción de condensados de Bose-Einstein de 41K y 39K. Además, se reporta la condensación de la mezcla degenerada 41K - 39K, la cual no había sido previamente reportada en la literatura. Estos resultados son los primeros de su tipo en España y por lo tanto abren un amplio panorama en el estudio de fenómenos cuánticos en el país. La mezcla cuántica reportada en esta tesis permite acceder a sistemas cuánticos novedosos en el campo de átomos fríos. El control de las interacciones atómicas es una herramienta ampliamente usada en el campo, por lo cual se han caracterizado las propiedades de dispersión en esta nueva mezcla, así como en diferentes mezclas de espín entre los isotopos 41K y 39K. El resultado más importante de esta tesis reside en la creación de un nuevo estado de la materia: una gota liquida cuántica ultra-diluida. Esta gota cuántica se compone de una mezcla de dos estados diferentes de espín de 39K. Este líquido se encuentra ligado por sí mismo debido a la compensación de las fuerzas atractivas de campo con el carácter repulsivo de efectos cuánticos que van más allá de la aproximación de campo medio. Este sistema sigue la idea original de D. Petrov, esta propone la formación de líquidos cuánticos usando mezclas de condensados de Bose-Einstein. En la primera serie de experimentos, hemos observado la formación de gotas cuánticas en un régimen donde una mezcla de Bose debería de colapsar de acuerdo con teorías de campo medio. Se ha medido su tamaño y ultra-baja densidad por medio de imágenes in situ. De esta manera confirma cómo este líquido permanece ligado por si mismo en la ausencia de confinamiento externo. Hemos demostrado que la existencia de estas gotas cuánticas se debe a una manifestación sorprendente de las fluctuaciones cuánticas. Finalmente hemos observado cómo debido a la presencia de la presión cuántica, debajo de un numero critico de átomos el sistema se disocia en gas dando lugar a una transición cuántica liquido-gas. Esta transición se ha medido experimentalmente como función de las interacciones atómicas entre los átomos. Estas mediciones traen consigo una pregunta intrigante: ¿Cuál es la diferencia entre nuestras gotas cuánticas y los ya conocidos solitones de materia? En una segunda serie de experimentos, hemos dado respuesta a esta interrogante al estudiar las propiedades de una mezcla de Bose confinada en una guía óptica. En este tipo de geometría ambos estados pueden existir. En analogía a sistemas ópticos no-lineales, solitones son sistemas estabilizados por efectos de dispersión, mientras las gotas cuánticas corresponden a solitones de más alta dimensión estabilizadas por efectos no lineales de alto orden. Hemos encontrado que, dependiendo del número de átomos, fuerza de interacción y confinamiento, solitones y gotas cuánticas son dos estados cuánticos que pueden estar conectados, permanecer como dos estados distintos, o coexistir en una región de bi-estabilidad. Se ha medido su composición de espín, densidad del sistema y encontrado experimentalmente la frontera que separa ambos sistemas. En conclusión, los experimentos mostrados en esta tesis demuestran la existencia de un nuevo liquido cuántico ultra-diluido estabilizado únicamente por interacciones de contacto. Su existencia es puramente debida a las fluctuaciones cuánticas presentes en el sistema. Este sistema provee una plataforma ideal para el estudio y la comprensión de teorías cuánticas más complejas las cuales van más allá de la aproximación de campo medio
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Quantum liquid droplets in a mixture of Bose-Einstein condensates
Universitat Politècnica de Catalunya, 2018Co-Authors: César RaymundoAbstract:In this thesis, we report on the design and construction of a quantum simulator experiment using quantum gases in Spain. This experiment exploits mixtures of the three Isotopes of Potassium, which give access in an original approach to the study of Bose-Bose or Bose-Fermi mixtures using the same experimental setup. We validate our experimental setup with the observation of a Bose-Einstein condensate (BEC) of 41K and 39K. Moreover we observe the dual Bose-Einstein condensation of 39K–41K. These results represents the first observation of BECs in Spain and give access to a novel quantum degenerate mixture in the field. Since the control of interactions in our experiment are crucial, we characterize the scattering properties of the 39K–41K mixture, and spin mixtures of 39K and 41K. In addition, using a spin mixture of 39K BEC, we report on the observation of a novel state of matter: a composite quantum liquid droplet. This dilute quantum droplet is a liquid-like cluster of ultra-cold atoms self-trapped by attractive mean-field forces and stabilized against collapse by repulsive beyond mean-field many-body effects. This system follows the original proposal where D. Petrov predicted the formation of self-bound liquid droplets in mixtures of Bose-Einstein condensates. In the first series of experiments, we have observed the formation of quantum droplets in a regime where the Bose-Bose mixture should collapse from the mean-field perspective.We directly measure the droplet size and ultra-low density via high-resolution in situ imaging, and experimentally confirm their self-bound nature.We demonstrate that the existence of these droplets is a striking manifestation of quantum fluctuations. These droplets do not exist in single-component condensates with described with contact interactions. Finally, we observe that for small atom numbers, quantum pressure dissociates the droplets and drives a liquid-to-gas transition, which we map out as a function of interaction strength. These measurements open an intriguing point of investigation: the difference existing between droplets and bright solitons. In the second series of experiments, we address it by placing the mixture in an optical waveguide, realizing a system that contains both composite bright solitons and quantum liquid droplets. In analogy to non-linear optics, the former can be seen as one-dimensional matter-wave solitons stabilized by dispersion, whereas the latter corresponds to highdimensional solitons stabilized by a higher order non-linearity. We find that depending on atom number, interaction strength and confinement, solitons and droplets can be smoothly connected or remain distinct states coexisting only in a bi-stable region. We measure their spin composition, extract their density for a broad range of parameters, and map out the boundary of the region separating solitons from droplets. Our experiments demonstrate a novel type of ultra-dilute quantum liquid, stabilized only by contact interactions. They provide an ideal platform for benchmarking complex quantum many-body theories beyond the mean-field approximation in a quantum simulation approach. Furthermore, they constitute a novel playground to explore experimentally self-bound states stabilized by unconventional higher order nonlinearities, relevant in non-linear optics.En este trabajo de tesis se reporta el diseño y la construcción de uno de los experimentos pioneros en España que permite realizar simulaciones cuánticas usando átomos ultra fríos. En este experimento se enfrían hasta alcanzar la degeneración cuántica los tres diferentes isotopos de potasio los cuales permiten, de manera particular y original, el estudio de mezclas cuánticas degeneradas de tipo Bose-Bose o Bose-Fermi. El funcionamiento del experimento es validado por medio de la producción de condensados de Bose-Einstein de 41K y 39K. Además, se reporta la condensación de la mezcla degenerada 41K - 39K, la cual no había sido previamente reportada en la literatura. Estos resultados son los primeros de su tipo en España y por lo tanto abren un amplio panorama en el estudio de fenómenos cuánticos en el país. La mezcla cuántica reportada en esta tesis permite acceder a sistemas cuánticos novedosos en el campo de átomos fríos. El control de las interacciones atómicas es una herramienta ampliamente usada en el campo, por lo cual se han caracterizado las propiedades de dispersión en esta nueva mezcla, así como en diferentes mezclas de espín entre los isotopos 41K y 39K. El resultado más importante de esta tesis reside en la creación de un nuevo estado de la materia: una gota liquida cuántica ultra-diluida. Esta gota cuántica se compone de una mezcla de dos estados diferentes de espín de 39K. Este líquido se encuentra ligado por sí mismo debido a la compensación de las fuerzas atractivas de campo con el carácter repulsivo de efectos cuánticos que van más allá de la aproximación de campo medio. Este sistema sigue la idea original de D. Petrov, esta propone la formación de líquidos cuánticos usando mezclas de condensados de Bose-Einstein. En la primera serie de experimentos, hemos observado la formación de gotas cuánticas en un régimen donde una mezcla de Bose debería de colapsar de acuerdo con teorías de campo medio. Se ha medido su tamaño y ultra-baja densidad por medio de imágenes in situ. De esta manera confirma cómo este líquido permanece ligado por si mismo en la ausencia de confinamiento externo. Hemos demostrado que la existencia de estas gotas cuánticas se debe a una manifestación sorprendente de las fluctuaciones cuánticas. Finalmente hemos observado cómo debido a la presencia de la presión cuántica, debajo de un numero critico de átomos el sistema se disocia en gas dando lugar a una transición cuántica liquido-gas. Esta transición se ha medido experimentalmente como función de las interacciones atómicas entre los átomos. Estas mediciones traen consigo una pregunta intrigante: ¿Cuál es la diferencia entre nuestras gotas cuánticas y los ya conocidos solitones de materia? En una segunda serie de experimentos, hemos dado respuesta a esta interrogante al estudiar las propiedades de una mezcla de Bose confinada en una guía óptica. En este tipo de geometría ambos estados pueden existir. En analogía a sistemas ópticos no-lineales, solitones son sistemas estabilizados por efectos de dispersión, mientras las gotas cuánticas corresponden a solitones de más alta dimensión estabilizadas por efectos no lineales de alto orden. Hemos encontrado que, dependiendo del número de átomos, fuerza de interacción y confinamiento, solitones y gotas cuánticas son dos estados cuánticos que pueden estar conectados, permanecer como dos estados distintos, o coexistir en una región de bi-estabilidad. Se ha medido su composición de espín, densidad del sistema y encontrado experimentalmente la frontera que separa ambos sistemas. En conclusión, los experimentos mostrados en esta tesis demuestran la existencia de un nuevo liquido cuántico ultra-diluido estabilizado únicamente por interacciones de contacto. Su existencia es puramente debida a las fluctuaciones cuánticas presentes en el sistema. Este sistema provee una plataforma ideal para el estudio y la comprensión de teorías cuánticas más complejas las cuales van más allá de la aproximación de campo medio.Postprint (published version
C. S. Unnikrishnan - One of the best experts on this subject based on the ideXlab platform.
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Sub-Doppler deep-cooled bosonic and fermionic Isotopes of Potassium in a compact 2D+–3D MOT set-up
Journal of Physics B: Atomic Molecular and Optical Physics, 2011Co-Authors: Vandna Gokhroo, G. Rajalakshmi, R Kollengode Easwaran, C. S. UnnikrishnanAbstract:We report the sub-Doppler deep-cooled three-dimensional magneto-optical trap (3D MOT) of the fermionic 40K and bosonic 39K Isotopes of Potassium loaded by a very compact 2D+ MOT with a novel optical design feature. The set-up is meant for studies on the quantum dynamics of a few fermionic and bosonic atoms in an optical dipole trap near and well within quantum degeneracy. The loading rate and atom numbers achieved in the compact simple set-up are comparable to those in the previous set-ups with more elaborate vacuum design. We attained relatively low temperatures of 34 and 30 µK for 39K and 40K after the sub-Doppler cooling process.
Guglielmo M. Tino - One of the best experts on this subject based on the ideXlab platform.
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Magneto-optical trapping of Fermionic Potassium atoms
Physical Review A, 1998Co-Authors: Francesco Saverio Cataliotti, Eric A. Cornell, Chiara Fort, Massimo Inguscio, Francesco Marin, Marco Prevedelli, Leonardo Ricci, Guglielmo M. TinoAbstract:We have trapped ${}^{40}\mathrm{K}$ in a vapor-cell magneto-optical trap starting from a natural abundance sample. This rare, weakly radioactive atom is a fermion. The number of trapped atoms is approximately 8000, with a density of $\ensuremath{\sim}{10}^{8}$ atoms/${\mathrm{cm}}^{3}$. Contrary to what is observed for the other Isotopes of Potassium, our data indicate that temperatures lower than the Doppler-cooling limit can be reached for ${}^{40}\mathrm{K}$. We discuss the interest of these results in view of possible experiments to study a degenerate Fermi gas.