Gustavo Telles

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Papers by Gustavo Telles

Dark-spot atomic beam slowing to load magneto-optical traps

by Gustavo Telles and Sergio Muniz

Technical Digest. Summaries of Papers Presented at the International Quantum Electronics Conference. Conference Edition. 1998 Technical Digest Series, Vol.7 (IEEE Cat. No.98CH36236), 1998

Summary form only given. Here, we present an alternative to conventional beam slowing and off-axi... more Summary form only given. Here, we present an alternative to conventional beam slowing and off-axis magneto optical trap (MOT) loading. A dark spot placed in the center of the slowing beam makes a shadow on the position of the trap, allowing a large flux of slow atoms to be captured into the trap, without being disturbed. We have characterized this

Estudo de colisões atômicas ultrafrias: mecanismos de perda e espectroscopia de fotoassociação

Colisões Inelásticas Frias em Amostras Heteronucleares obtidas em Armadilhas Magneto-Ópticas

Characteristics and Perspectives of Quantum Turbulence in Atomic Bose-Einstein Condensates

by Gustavo Telles, Jorge Amin Seman, Pedro Tavares, Guilherme Bagnato, and Sergio Muniz

Springer Series in Solid-State Sciences, 2013

High resolution spectroscopy of Na 5S/sub 1/2/ hyperfine splitting using cold atoms

by Gustavo Telles and Sergio Muniz

Technical Digest. Summaries of Papers Presented at the Quantum Electronics and Laser Science Conference, 1999

ABSTRACT

Measuring the heat capacity in a Bose-Einstein condensation using global variables

by Gustavo Telles and Sergio Muniz

Physical Review A, 2014

Phase transitions are well understood and generally followed by the behavior of the associated th... more Phase transitions are well understood and generally followed by the behavior of the associated thermodynamic quantities, such as in the case of the λ point superfluid transition of liquid helium, which is observed in its heat capacity. In the case of a trapped Bose-Einstein condensate (BEC), the heat capacity cannot be directly measured. In this work, we present a technique able to determine the global heat capacity from the density distribution of a weakly interacting gas trapped in an inhomogeneous potential. This approach represents an alternative to models based on local density approximation. By defining a pair of global conjugate variables, we determine the total internal energy and its temperature derivative, the heat capacity. We then apply the technique to a trapped 87 Rb BEC a λ-type transition dependent on the atom number is observed, and the deviations from the non-interacting, ideal gas case are discussed. Finally we discuss the chances of using this method to study the heat capacity at T → 0.

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Collisional studies in cold binary mixtures

by Gustavo Telles and Sergio Muniz

Technical Digest. Summaries of papers presented at the Quantum Electronics and Laser Science Conference. Postconference Technical Digest (IEEE Cat. No.01CH37172), 2001

Summary form only given. We present a set of experimental results of trap loss rate for the follo... more Summary form only given. We present a set of experimental results of trap loss rate for the following mixtures: Na-Rb, K-Rb, Na-K, Rb-Cs and Cs-K. The analysis of our data set allows us to conclude that radiative escape is the main loss mechanism and we observed the significant contribution of the double-excited potential (both atoms excited) for the losses on

Studies of cold collisions in trapped alkali mixture

by Gustavo Telles and Sergio Muniz

Technical Digest. Summaries of Papers Presented at the International Quantum Electronics Conference. Conference Edition. 1998 Technical Digest Series, Vol.7 (IEEE Cat. No.98CH36236), 1998

Summary form only given. We have developed a new vapor cell for a magneto-optical trap (MOT) that... more Summary form only given. We have developed a new vapor cell for a magneto-optical trap (MOT) that has the capability of trapping two different species simultaneously and independently. Currently, we can trap any pair involving two of the following atoms: Na, K, Rb, and Cs. Our experimental setup consists of a cylindrical stainless steel chamber with four reservoirs. These independent

Investigation in a Mixture of Atomic and Molecular Cold Plasma in a Mot

Characterization of a dipole optical trap for imprison of neutral molecules

by Gustavo Telles and Jader Cabral

Experimental Measurement of the Momentum Structure of an Atomic Bose-Einstein Condensate

Vanderlei Salvador Bagnato (IFSC-USP) Silvio A. Vitiello (IFGW-UNICAMP) Local Committee Daniel V. Magalhaes (IFSC-USP)

by Gustavo Telles, Marios Tsatsos, and Sergio Muniz

Heteronuclear cold molecules laser spectroscopy

Summaries of Papers Presented at the Quantum Electronics and Laser Science Conference, 2002

ABSTRACT Summary form only given. In order to characterize the K-Cs sample we performed trap loss... more ABSTRACT Summary form only given. In order to characterize the K-Cs sample we performed trap loss measurements to evaluate the heteronuclear losses introduced by the overlapped samples one to each other. We present the heteronuclear loss rate observed on a cesium magneto-optical trap (MOT) due to collisions with the cold potassium atoms as a function of the Cs trap laser intensity. The result shows that the heteronuclear collisions are not likely to compromise the MOT number and density of trapped atoms. For the regular experimental conditions, very few heteronuclear molecules are expected to be produced. Therefore, to get better signal to noise ratio we decided to apply the pulsed ion production technique. Briefly, in the experiment there are two phases: trapping and probe. During the trap phase, the heteronuclear excited quasimolecules are photoassociated and during the probe phase they are photoionized by a laser pulse. The ions are collected by a channeltron and by the time-of-flight one may distinguish between the atomic and the molecular ions. The time diagram representing the experiment is shown. By scanning the frequency of the photoassociating probe laser, we shall be able to measure the bound states of the K-Cs molecule, and then to obtain the heteronuclear scattering length.

Power Law on the Kinetic Energy Spectrum of a Turbulent Atomic Superfluid

Latin America Optics and Photonics Conference, 2012

ABSTRACT We report the observation of a scaling power law existing in the kinetic energy spectrum... more

Optical suppression of hyperfine-changing collisions in a sample of ultracold sodium atoms

by Gustavo Telles, J. Weiner, and Sergio Muniz

... Marcassa, R. Napolitano, GD Telles, J. Weiner,* SC Zilio, and VS BagnatoInstituto de Fi&a... more ... Marcassa, R. Napolitano, GD Telles, J. Weiner,* SC Zilio, and VS BagnatoInstituto de Fi&amp;amp;amp;amp;amp;amp;amp;#x27;sica de Sa~o Carlos, Universidade de Sa~o Paulo, Caixa Postal 369, Sa~o Carlos, Sa~o Paulo 13560-970, Brazil ~Received 29 May 1996; revised manuscript received 13 February 1997! ...

Inelastic cold collisions of a Na/Rb mixture in a magneto-optical trap

by Gustavo Telles and Sergio Muniz

Inelastic cold collisions of a Na/Rb mixture in a magneto-optical trap. GD Telles, LG Marcassa, S... more

Collision dynamics of magnetically trapped Na and Rb

We present a study of the collision dynamics of a dual species sample of magnetically trapped ^23... more We present a study of the collision dynamics of a dual species sample of magnetically trapped ^23Na and ^87Rb atoms. Careful control of loading dynamics and internal state preparation was necessary to minimize inter-species trap losses. Simultaneous magnetic trapping of the two species in the |1,-1> state was achieved with lifetimes of several seconds, which suggests an absence of strong

Characterization of LIAD loaded sodium MOT

We present a compact ultrahigh vacuum (UHV) vapor cell for magneto-optical trapping (MOT) of sodi... more We present a compact ultrahigh vacuum (UHV) vapor cell for magneto-optical trapping (MOT) of sodium atoms. Our system features light-induced atomic desorption (LIAD) loading. LIAD at short wavelengths (375 nm and 455 nm) was used, allowing for fast switching and control of the sodium vapor pressure. We have used a single laser beam which passes through an electro-optic modulator to

Progress Towards a Dual BEC of Na Rb

We report on the status of a dual species atomic Bose-Einstein condensate of ^23Na and ^87Rb. Our... more We report on the status of a dual species atomic Bose-Einstein condensate of ^23Na and ^87Rb. Our apparatus has been specially built to investigate the collisional dynamics and properties of this unique mixture of alkali metal atoms, including kilogauss magnetic field capability and high optical access. Our approach incorporates a Zeeman slower capable of delivering a large flux of both

Mechanism of Vortices Generation for a Trapped Superfluid under Oscillatory Excitation

by Gustavo Telles and Pedro Tavares

Latin America Optics and Photonics Conference, 2012

The vortex nucleation and the emergence of quantum turbulence induced by oscillating magnetic fie... more The vortex nucleation and the emergence of quantum turbulence induced by oscillating magnetic fields, introduced by [1, 2], left a few open questions concerning the basic mechanisms causing those interesting phenomema. Here, we report the experimental observation of the slosh dynamics of a magnetically trapped 87 Rb Bose-Einstein condensate (BEC) under the influence of a time-varying magnetic field. We observed a clear relative displacement in between the condensed and the thermal fraction center-of-mass. We have identified this relative counter move as an out-of-phase oscillation mode, which is able to produce ripples on the condensed/thermal fractions interface. The out-ofphase mode provides good evidences of a mechanism involved in the vortex nucleation and evolution when excited by time dependent magnetic fields.

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