<?xml version="1.0" encoding="utf-8"?>
<!DOCTYPE article SYSTEM "archivearticle3.dtd">
<article dtd-version="3.0" article-type="Invited Methods Article - JoVE Produced Video">
  <front>
    <journal-meta>
      <journal-id journal-id-type="publisher">jove</journal-id>
      <journal-id journal-id-type="email">editorial-office@jove.com</journal-id>
      <journal-title-group>
        <journal-title>Journal of Visualized Experiments</journal-title>
      </journal-title-group>
      <issn pub-type="ppub">1940-087X</issn>
      <issn pub-type="epub"></issn>
    </journal-meta>
    <article-meta>
      <article-id pub-id-type="publisher-id">JoVE55409</article-id>
      <article-id pub-id-type="manuscript">JoVE55409</article-id>
      <article-categories>
        <subj-group subj-group-type="Article Type">
          <subject>Invited Methods Article - JoVE Produced Video</subject>
        </subj-group>
        <subj-group subj-group-type="Category">
          <subject>JoVE Engineering</subject>
        </subj-group>
        <subj-group subj-group-type="Classification">
          <subject>Atomic and Molecular Physics</subject>
          <subject>Optics</subject>
        </subj-group>
      </article-categories>
      <title-group>
        <article-title>Cooling an optically-trapped ultracold Fermi gas by periodical driving</article-title>
      </title-group>
      <contrib-group>
        <contrib contrib-type="author">
          <role content-type="1" />
          <name>
            <surname>Li</surname>
            <given-names>Jiaming</given-names>
          </name>
          <email>jiamli@iupui.edu</email>
          <xref ref-type="aff" rid="aff1" />
        </contrib>
        <contrib contrib-type="author">
          <role content-type="2" />
          <name>
            <surname>de Melo</surname>
            <given-names>Leonardo</given-names>
          </name>
          <email>ldemelo@iupui.edu</email>
          <xref ref-type="aff" rid="aff2" />
        </contrib>
        <contrib contrib-type="author" corresp="yes">
          <role content-type="3" />
          <name>
            <surname>Luo</surname>
            <given-names>Le</given-names>
            <prefix>Dr.</prefix>
          </name>
          <degrees>Ph.D.</degrees>
          <email>leluo@iupui.edu</email>
          <xref ref-type="aff" rid="aff3" />
        </contrib>
        <contrib contrib-type="editor">
          <name>
            <surname>Bittner</surname>
            <given-names>Alycia</given-names>
          </name>
          <degrees>Ph.D.</degrees>
          <email>alycia.bittner@jove.com</email>
          <xref ref-type="aff" rid="aff4" />
        </contrib>
        <aff id="aff1">
          <institution>Indiana University Purdue University at Indianapolis</institution>
          <addr-line content-type="addrline1">402 N. Blackford St.</addr-line>
          <addr-line content-type="addrline2">LD 154</addr-line>
          <country>UNITED STATES</country>
          <addr-line content-type="city">Indianapolis</addr-line>
          <addr-line content-type="zipcode">46202</addr-line>
        </aff>
        <aff id="aff2">
          <institution>Indiana University Purdue University at Indianapolis</institution>
          <addr-line content-type="addrline1">402 N. Blackford St.</addr-line>
          <addr-line content-type="addrline2">LD 154</addr-line>
          <country>UNITED STATES</country>
          <addr-line content-type="city">Indianapolis</addr-line>
          <addr-line content-type="zipcode">46202</addr-line>
        </aff>
        <aff id="aff3">
          <institution>Indiana University Purdue University at Indianapolis</institution>
          <institution content-type="position">Assistant Professor</institution>
          <institution content-type="dept">Physics</institution>
          <addr-line content-type="addrline1">402 N Balckford St LD154</addr-line>
          <addr-line content-type="addrline2">Physics Dept</addr-line>
          <addr-line content-type="addrline4">United States</addr-line>
          <country>UNITED STATES</country>
          <addr-line content-type="city">Indianapolis</addr-line>
          <addr-line content-type="state">Indiana</addr-line>
          <addr-line content-type="zipcode">46202</addr-line>
          <fax>3172746910</fax>
          <phone content-type="primary">3172746910</phone>
          <institution>Indiana University Purdue University at Indianapolis</institution>
        </aff>
        <aff id="aff4">
          <institution>JoVE</institution>
          <addr-line>1 Alewife Center</addr-line>
          <addr-line>Suite 200</addr-line>
          <addr-line>Cambridge, MA  02140</addr-line>
          <country>UNITED STATES</country>
        </aff>
      </contrib-group>
      <history>
        <date date-type="received">
          <day>30</day>
          <month>08</month>
          <year>2016</year>
        </date>
        <date date-type="rev-recd">
          <day>15</day>
          <month>11</month>
          <year>2016</year>
        </date>
        <date date-type="rev-recd">
          <day>27</day>
          <month>09</month>
          <year>2016</year>
        </date>
        <date date-type="rev-recd">
          <day>07</day>
          <month>09</month>
          <year>2016</year>
        </date>
        <date date-type="accepted">
          <day>17</day>
          <month>11</month>
          <year>2016</year>
        </date>
      </history>
      <abstract>
        <p>We present a cooling method for a cold Fermi gas by parametrically driving atomic motions in a crossed-beam optical dipole trap (ODT). Our method employs the anharmonicity of the ODT, in which the hotter atoms at the edge of the trap feel the anharmonic components of the trapping potential, while the colder atoms in the center of the trap feel the harmonic one. By modulating the trap depth with frequencies that are resonant with the anharmonic components, we selectively excite the hotter atoms out of the trap while keeping the colder atoms in the trap, generating parametric cooling. This experimental protocol starts with a magneto-optical trap (MOT) that is loaded by a Zeeman slower. The precooled atoms in the MOT are then transferred to an ODT, and a bias magnetic field is applied to create an interacting Fermi gas. We then lower the trapping potential to prepare a cold Fermi gas near the degenerate temperature. After that, we sweep the magnetic field to the noninteracting regime of the Fermi gas, in which the parametric cooling can be manifested by modulating the intensity of the optical trapping beams. We find that the parametric cooling effect strongly depends on the modulation frequencies and amplitudes. With the optimized frequency and amplitude, we measure the dependence of the cloud energy on the modulation time. We observe that the cloud energy is changed in an anisotropic way, where the energy of the axial direction is significantly reduced by parametric driving. The cooling effect is limited to the axial direction because the dominant anharmonicity of the crossed-beam ODT is along the axial direction. Finally, we propose to extend this protocol for the trapping potentials of large anharmonicity in all directions, which provides a promising scheme for cooling quantum gases using external driving.</p>
      </abstract>
      <kwd-group>
        <kwd>Laser Cooling</kwd>
        <kwd>Laser Trapping</kwd>
        <kwd>Ultracold Atoms</kwd>
        <kwd>Optical Dipole Trap</kwd>
        <kwd>Parametric Cooling</kwd>
        <kwd>Degenerate Fermi Gas</kwd>
      </kwd-group>
      <funding-group />
      <counts>
        <fig-count count="0" />
      </counts>
      <custom-meta-group>
        <custom-meta>
          <meta-name>If the protocol section of this manuscript is longer than 3 pages, are the most important steps highlighted (up to 2.75 pages)?&lt;/br&gt;
&lt;/br&gt;
This is &lt;b&gt;required &lt;/b&gt; for protocols longer than 3 pages, properly formatted (12 pt font, single spaced, space between each step, 1" margins, no indentations). Please see &lt;a href="http://www.jove.com/files/Instructions_for_Authors.pdf"&gt;JoVE Manuscript Instructions for Authors&lt;/a&gt; for more clarification. Remember that the non-highlighted protocol steps will remain in the manuscript and therefore will still be available to the reader. 
&lt;br/&gt;&lt;br/&gt;&lt;b&gt;Type 'Yes' or if needed, provide further explanation.&lt;/b&gt;</meta-name>
          <meta-value>Yes</meta-value>
        </custom-meta>
        <custom-meta>
          <meta-name>Please indicate whether this article will be standard or open access. </meta-name>
          <meta-value>Standard Access (US$2,400);</meta-value>
        </custom-meta>
        <custom-meta>
          <meta-name>Please indicate the &lt;b&gt; full address&lt;/b&gt; at which this article will be &lt;b&gt;filmed&lt;/b&gt;.</meta-name>
          <meta-value>402 N. Blackford St., LD019, Indianapolis, IN 46202</meta-value>
        </custom-meta>
        <custom-meta>
          <meta-name>If the invoicing address and point of contact are different than the corresponding author and filming address, please note the differences below.</meta-name>
          <meta-value>402 N. Blackford St.
LD 154
Indianapolis, IN 46202</meta-value>
        </custom-meta>
        <custom-meta>
          <meta-name>Is all of the written text in your manuscript original (not plagiarized, or self-plagiarized)? If using previously published figures, are re-use permissions from the previous publishers obtained and cited in the figure legends?</meta-name>
          <meta-value>Yes</meta-value>
        </custom-meta>
        <custom-meta>
          <meta-name>Black and White Image Count</meta-name>
          <meta-value>0</meta-value>
        </custom-meta>
        <custom-meta>
          <meta-name>Color Image Count</meta-name>
          <meta-value>0</meta-value>
        </custom-meta>
        <custom-meta>
          <meta-name>Production Notes</meta-name>
          <meta-value>Visualization: Please provide labeled, photographic images of the setup/equipment. These can be provided as supplemental files. In addition, many of the steps in the protocol do not make it clear when actions will be performed in software and automated versus when the experimenter is manipulating the software or equipment. 

Response: We will provide labeled images of our setup/equipment after the peer review as discussed previously. We have indicated if the steps are done manually or via software control.</meta-value>
        </custom-meta>
        <custom-meta>
          <meta-name>Acquisitions Editor</meta-name>
          <meta-value>Benjamin Werth</meta-value>
        </custom-meta>
        <custom-meta>
          <meta-name>Assistant who entered lead</meta-name>
          <meta-value>Neelima Chandrayan</meta-value>
        </custom-meta>
      </custom-meta-group>
    </article-meta>
  </front>
  <body>
    <fig>
      <label>Figure1</label>
      <graphic xlink:href="Fig1.pdf" xmlns:xlink="http://www.w3.org/1999/xlink" />
    </fig>
    <fig>
      <label>Figure2</label>
      <graphic xlink:href="Fig2.pdf" xmlns:xlink="http://www.w3.org/1999/xlink" />
    </fig>
    <fig>
      <label>Figure3</label>
      <graphic xlink:href="Fig3.pdf" xmlns:xlink="http://www.w3.org/1999/xlink" />
    </fig>
    <fig>
      <label>Figure4</label>
      <graphic xlink:href="Fig4.pdf" xmlns:xlink="http://www.w3.org/1999/xlink" />
    </fig>
    <table-wrap>
      <label>Table1</label>
      <graphic xlink:href="Table1.pdf" xmlns:xlink="http://www.w3.org/1999/xlink" />
    </table-wrap>
    <table-wrap>
      <label>Table2</label>
      <graphic xlink:href="Table2.pdf" xmlns:xlink="http://www.w3.org/1999/xlink" />
    </table-wrap>
    <table-wrap>
      <label>Excel Spreadsheet- Table of Materials/Equipment</label>
      <graphic xlink:href="Jove-materials list.xlsx" xmlns:xlink="http://www.w3.org/1999/xlink" />
    </table-wrap>
    <fig>
      <label>Figure2</label>
      <graphic xlink:href="Fig2Revised.pdf" xmlns:xlink="http://www.w3.org/1999/xlink" />
    </fig>
    <fig>
      <label>Figure3</label>
      <graphic xlink:href="Fig3Revised.pdf" xmlns:xlink="http://www.w3.org/1999/xlink" />
    </fig>
    <table-wrap>
      <label>Table1</label>
      <graphic xlink:href="Table1Revised.xlsx" xmlns:xlink="http://www.w3.org/1999/xlink" />
    </table-wrap>
    <table-wrap>
      <label>Table2</label>
      <graphic xlink:href="Table2Revised.xlsx" xmlns:xlink="http://www.w3.org/1999/xlink" />
    </table-wrap>
    <fig>
      <label>Figure</label>
      <graphic xlink:href="Figure1.pdf" xmlns:xlink="http://www.w3.org/1999/xlink" />
    </fig>
    <fig>
      <label>Figure</label>
      <graphic xlink:href="Figure2.pdf" xmlns:xlink="http://www.w3.org/1999/xlink" />
    </fig>
    <fig>
      <label>Figure</label>
      <graphic xlink:href="Figure3.pdf" xmlns:xlink="http://www.w3.org/1999/xlink" />
    </fig>
    <fig>
      <label>Figure</label>
      <graphic xlink:href="Figure4.pdf" xmlns:xlink="http://www.w3.org/1999/xlink" />
    </fig>
    <fig>
      <label>Figure</label>
      <graphic xlink:href="Figure5.pdf" xmlns:xlink="http://www.w3.org/1999/xlink" />
    </fig>
    <table-wrap>
      <label>Table</label>
      <graphic xlink:href="Table 1.xlsx" xmlns:xlink="http://www.w3.org/1999/xlink" />
    </table-wrap>
    <table-wrap>
      <label>Table</label>
      <graphic xlink:href="Table 2.xlsx" xmlns:xlink="http://www.w3.org/1999/xlink" />
    </table-wrap>
    <table-wrap>
      <label>Table</label>
      <graphic xlink:href="Table 3.xlsx" xmlns:xlink="http://www.w3.org/1999/xlink" />
    </table-wrap>
    <table-wrap>
      <label>Excel Spreadsheet- Table of Materials/Equipment</label>
      <graphic xlink:href="Materials list.xlsx" xmlns:xlink="http://www.w3.org/1999/xlink" />
    </table-wrap>
    <fig>
      <label>Figure</label>
      <graphic xlink:href="Figure 1.pdf" xmlns:xlink="http://www.w3.org/1999/xlink" />
    </fig>
    <fig>
      <label>Figure</label>
      <graphic xlink:href="Figure 2.pdf" xmlns:xlink="http://www.w3.org/1999/xlink" />
    </fig>
    <fig>
      <label>Figure</label>
      <graphic xlink:href="Figure 3.pdf" xmlns:xlink="http://www.w3.org/1999/xlink" />
    </fig>
    <fig>
      <label>Figure</label>
      <graphic xlink:href="Figure 4.pdf" xmlns:xlink="http://www.w3.org/1999/xlink" />
    </fig>
    <fig>
      <label>Figure</label>
      <graphic xlink:href="Figure 5.pdf" xmlns:xlink="http://www.w3.org/1999/xlink" />
    </fig>
    <fig>
      <label>Figure</label>
      <graphic xlink:href="Figure 6.pdf" xmlns:xlink="http://www.w3.org/1999/xlink" />
    </fig>
    <fig>
      <label>Figure</label>
      <graphic xlink:href="Figure 7.pdf" xmlns:xlink="http://www.w3.org/1999/xlink" />
    </fig>
    <fig>
      <label>Figure</label>
      <graphic xlink:href="Figure 8.pdf" xmlns:xlink="http://www.w3.org/1999/xlink" />
    </fig>
    <fig>
      <label>Figure</label>
      <graphic xlink:href="Figure 9.pdf" xmlns:xlink="http://www.w3.org/1999/xlink" />
    </fig>
  </body>
</article>