Re: Why can a photon only interfere with itself across multiple universes but not with other photons in the same universe?

smitra-RSh1/+X/PmFmR6Xm/[email protected] Tue, 07 Jan 2014 15:40:07 +0100
Newsgroups	gmane.science.physics.fabric-of-reality
Message-ID	<[email protected]>
--wTvBNFFkpcYD2LRcFkK7oz5DxG4LhjVDYqmQSXT
Content-Type: text/plain; charset=ISO-8859-1
Content-Transfer-Encoding: 7bit

Citeren [email protected]:

> David Deutsch wrote:
>
>>> This is something that has bugged me for a while:
>>>
>>> Why can a photon only interfere with itself across multiple 
>>> universes (interference), but can't interact with other photos in 
>>> the same universe? i.e, why don't two photons interact when fired 
>>> directly at each other?, and yet the same photon can interfere with 
>>> itself across multiple universes?
>>
>> Quantum theory describes nature according to certain laws of motion.
>
> These laws do not refer to universes or interference. Those are 
> approximate terms. The laws predict that photons in a vacuum do not 
> interact with each other, but that a single photon in a suitable 
> interferometer interacts strongly with itself. Two or more photons in 
> a suitable interferometer interact with each other as well as with 
> themselves.
>
> Thanks. If you could build a light source that emitted light at the 
> same phase and frequency, would the photos interfere with each other? 
> Or is there more to it?

What happens when you get interference from two coherent light sources 
is that each photon can be emitted from eiter source and these two 
possibilities interfere with each other, precisely analogous to the two 
slit experiment.

Saibal

--wTvBNFFkpcYD2LRcFkK7oz5DxG4LhjVDYqmQSXT
Content-Type: text/html; charset=ISO-8859-1
Content-Transfer-Encoding: 7bit




<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN" "http://www.w3.org/TR/html4/strict.dtd">
<html>
<head>
</head>







<body style="background-color: #fff;">
<span style="display:none">&nbsp;</span>

<!--~-|**|PrettyHtmlStartT|**|-~-->
<div id="ygrp-mlmsg" style="position:relative;">
  <div id="ygrp-msg" style="z-index: 1;">
<!--~-|**|PrettyHtmlEndT|**|-~-->

    <div id="ygrp-text" >
      
      
      <p>Citeren [email protected]:<br>
<br>
&gt; David Deutsch wrote:<br>
&gt;<br>
&gt;&gt;&gt; This is something that has bugged me for a while:<br>
&gt;&gt;&gt;<br>
&gt;&gt;&gt; Why can a photon only interfere with itself across multiple <br>
&gt;&gt;&gt; universes (interference), but can&#39;t interact with other photos in <br>
&gt;&gt;&gt; the same universe? i.e, why don&#39;t two photons interact when fired <br>
&gt;&gt;&gt; directly at each other?, and yet the same photon can interfere with <br>
&gt;&gt;&gt; itself across multiple universes?<br>
&gt;&gt;<br>
&gt;&gt; Quantum theory describes nature according to certain laws of motion.<br>
&gt;<br>
&gt; These laws do not refer to universes or interference. Those are <br>
&gt; approximate terms. The laws predict that photons in a vacuum do not <br>
&gt; interact with each other, but that a single photon in a suitable <br>
&gt; interferometer interacts strongly with itself. Two or more photons in <br>
&gt; a suitable interferometer interact with each other as well as with <br>
&gt; themselves.<br>
&gt;<br>
&gt; Thanks. If you could build a light source that emitted light at the <br>
&gt; same phase and frequency, would the photos interfere with each other? <br>
&gt; Or is there more to it?<br>
<br>
What happens when you get interference from two coherent light sources <br>
is that each photon can be emitted from eiter source and these two <br>
possibilities interfere with each other, precisely analogous to the two <br>
slit experiment.<br>
<br>
Saibal<br>
</p>

    </div>
     

    <!--~-|**|PrettyHtmlStart|**|-~-->
    <div style="color: #fff; height: 0;">__._,_.___</div>

          
  
    
    <table cellspacing=4px style="margin-top: 20px; margin-bottom: 10px;">
      <tbody>
        <tr>
          <td style="font-size: 12px; font-family: arial; font-weight: bold; padding: 7px 5px 5px; color: #FFF; background-color: #F2F2F2; border: 1px solid #EAEAEA "  >
                          <a style="text-decoration: none; color: #2D50FD" href="http://groups.yahoo.com/group/Fabric-of-Reality/post;_ylc=X3oDMTJxa3ZxcHNpBF9TAzk3MzU5NzE0BGdycElkAzE4ODg2MDAEZ3Jwc3BJZAMxNzA1MDIwNTg1BG1zZ0lkAzI1NjE4BHNlYwNmdHIEc2xrA3JwbHkEc3RpbWUDMTM4OTExNzc2Mw--?act=reply&messageNum=25618">Reply via web post</a>
                      </td>
          <td style="font-size: 12px; font-family: arial; padding: 7px 5px 5px; color: #FFF; background-color: #F2F2F2; border: 1px solid #EAEAEA; " >
            <a href="mailto:smitra-RSh1/+X/PmFmR6Xm/[email protected]?subject=Re%3A%20Why%20can%20a%20photon%20only%20interfere%20with%20itself%20across%20multiple%09universes%20but%20not%20with%20other%20photons%20in%20the%20same%20universe%3F" style="text-decoration: none; color: #2D50FD;">
              Reply to sender            </a> 
          </td>
          <td style="font-size: 12px; font-family: arial; padding: 7px 5px 5px; color: #FFF; background-color: #F2F2F2; border: 1px solid #EAEAEA; ">
            <a href="mailto:[email protected]?subject=Re%3A%20Why%20can%20a%20photon%20only%20interfere%20with%20itself%20across%20multiple%09universes%20but%20not%20with%20other%20photons%20in%20the%20same%20universe%3F" style="text-decoration: none; color: #2D50FD">
              Reply to group            </a> 
          </td>
          <td style="font-size: 12px; font-family: arial; padding: 7px 5px 5px; color: #FFF; background-color: #F2F2F2; border: 1px solid #EAEAEA; " >
            <a href="http://groups.yahoo.com/group/Fabric-of-Reality/post;_ylc=X3oDMTJldGlpcjk5BF9TAzk3MzU5NzE0BGdycElkAzE4ODg2MDAEZ3Jwc3BJZAMxNzA1MDIwNTg1BHNlYwNmdHIEc2xrA250cGMEc3RpbWUDMTM4OTExNzc2Mw--" style="text-decoration: none; color: #2D50FD">Start a New Topic</a>
          </td>
          <td style="font-size: 12px; font-family: arial; padding: 7px 5px 5px; color: #2D50FD; background-color: #F2F2F2; border: 1px solid #EAEAEA; " >
                            <a href="http://groups.yahoo.com/group/Fabric-of-Reality/message/25614;_ylc=X3oDMTM2OTZ0aWk3BF9TAzk3MzU5NzE0BGdycElkAzE4ODg2MDAEZ3Jwc3BJZAMxNzA1MDIwNTg1BG1zZ0lkAzI1NjE4BHNlYwNmdHIEc2xrA3Z0cGMEc3RpbWUDMTM4OTExNzc2MwR0cGNJZAMyNTYxNA--" style="text-decoration: none; color: #2D50FD;">Messages in this topic</a>
                (4)
                      </td>
        </tr>
      </tbody>
    </table>

        
<!------- Start Nav Bar ------>

<!-- |**|begin egp html banner|**| -->
<div id="ygrp-vital" style="background-color: #f2f2f2; font-family: Verdana; font-size: 10px; margin-bottom: 10px; padding: 10px;">
      <span id="vithd" style="font-weight: bold; color: #333; text-transform: uppercase; ">Recent Activity:</span>

    <ul style="list-style-type: none; margin: 0; padding: 0; display: inline;">
                                                    </ul>
    
  <div style="clear: both; padding-top: 2px; color: #1e66ae;">
    <a href="http://groups.yahoo.com/group/Fabric-of-Reality;_ylc=X3oDMTJlNDQ5Z25xBF9TAzk3MzU5NzE0BGdycElkAzE4ODg2MDAEZ3Jwc3BJZAMxNzA1MDIwNTg1BHNlYwN2dGwEc2xrA3ZnaHAEc3RpbWUDMTM4OTExNzc2Mw--" style="text-decoration: none;">Visit Your Group</a>
  </div>
</div>


  
<div id="ft" style="font-family: Arial; font-size: 11px; margin-top: 5px; padding: 0 2px 0 0; clear: both;">
  <a href="http://groups.yahoo.com/;_ylc=X3oDMTJkYWUybmRjBF9TAzk3MzU5NzE0BGdycElkAzE4ODg2MDAEZ3Jwc3BJZAMxNzA1MDIwNTg1BHNlYwNmdHIEc2xrA2dmcARzdGltZQMxMzg5MTE3NzYz" style="float: left;"><img src="http://l.yimg.com/ru/static/images/yg/img/email/new_logo/logo-groups-137x15.png" height="15" width="137" alt="Yahoo! Groups" style="border: 0;"/></a>
  <div style="color: #747575; float: right;">Switch to: <a href="mailto:Fabric-of-Reality-traditional-hHKSG33TihhbjbujkaE4pw@public.gmane.org?subject=Change Delivery Format: Traditional" style="text-decoration: none;">Text-Only</a>, <a href="mailto:[email protected]?subject=Email Delivery: Digest" class="margin-rt" style="text-decoration: none;">Daily Digest</a> &bull; <a href="mailto:Fabric-of-Reality-unsubscribe-hHKSG33TihhbjbujkaE4pw@public.gmane.org?subject=Unsubscribe" style="text-decoration: none;">Unsubscribe</a> &bull; <a href="http://info.yahoo.com/legal/us/yahoo/utos/terms/" style="text-decoration: none;">Terms of Use</a> &bull; <a href="mailto:[email protected]?subject=Feedback on the redesigned individual mail v1" style="text-decoration: none;">Send us Feedback </a></div>
</div>

<!-- |**|end egp html banner|**| -->

  </div> <!-- ygrp-msg -->

  <!-- Sponsor -->
  <!-- |**|begin egp html banner|**| -->
  <div id="ygrp-sponsor" style="width:160px; float:right; clear:none; margin:0 0 25px 0; background: #fff;">

<!-- Start Recommendations -->
<div id="ygrp-reco">
     </div>
<!-- End Recommendations -->



  </div>   <!-- |**|end egp html banner|**| -->

  <div style="clear:both; color: #FFF; font-size:1px;">.</div>
</div>

  <img src="http://geo.yahoo.com/serv?s=97359714/grpId=1888600/grpspId=1705020585/msgId=25618/stime=1389117763" width="1" height="1"> <br>

<div style="color: #fff; height: 0;">__,_._,___</div>
<!--~-|**|PrettyHtmlEnd|**|-~-->

</body>

<!--~-|**|PrettyHtmlStart|**|-~-->
<head>
  <style type="text/css">
  <!--
  #ygrp-mkp {
  border: 1px solid #d8d8d8;
  font-family: Arial;
  margin: 10px 0;
  padding: 0 10px;
}

#ygrp-mkp hr {
  border: 1px solid #d8d8d8;
}

#ygrp-mkp #hd {
  color: #628c2a;
  font-size: 85%;
  font-weight: 700;
  line-height: 122%;
  margin: 10px 0;
}

#ygrp-mkp #ads {
  margin-bottom: 10px;
}

#ygrp-mkp .ad {
  padding: 0 0;
}

#ygrp-mkp .ad p {
  margin: 0;
}

#ygrp-mkp .ad a {
  color: #0000ff;
  text-decoration: none;
}
  #ygrp-sponsor #ygrp-lc {
  font-family: Arial;
}

#ygrp-sponsor #ygrp-lc #hd {
  margin: 10px 0px;
  font-weight: 700;
  font-size: 78%;
  line-height: 122%;
}

#ygrp-sponsor #ygrp-lc .ad {
  margin-bottom: 10px;
  padding: 0 0;
}

  #actions {
    font-family: Verdana;
    font-size: 11px;
    padding: 10px 0;
  }

  #activity {
    background-color: #e0ecee;
    float: left;
    font-family: Verdana;
    font-size: 10px;
    padding: 10px;
  }

  #activity span {
    font-weight: 700;
  }

  #activity span:first-child {
    text-transform: uppercase;
  }

  #activity span a {
    color: #5085b6;
    text-decoration: none;
  }

  #activity span span {
    color: #ff7900;
  }

  #activity span .underline {
    text-decoration: underline;
  }

  .attach {
    clear: both;
    display: table;
    font-family: Arial;
    font-size: 12px;
    padding: 10px 0;
    width: 400px;
  }

  .attach div a {
    text-decoration: none;
  }

  .attach img {
    border: none;
    padding-right: 5px;
  }

  .attach label {
    display: block;
    margin-bottom: 5px;
  }

  .attach label a {
    text-decoration: none;
  }
  
  blockquote {
    margin: 0 0 0 4px;
  }

  .bold {
    font-family: Arial;
    font-size: 13px;
    font-weight: 700;
  }

  .bold a {
    text-decoration: none;
  }

  dd.last p a {
    font-family: Verdana;
    font-weight: 700;
  }

  dd.last p span {
    margin-right: 10px;
    font-family: Verdana;
    font-weight: 700;
  }

  dd.last p span.yshortcuts {
    margin-right: 0;
  }

  div.attach-table div div a {
    text-decoration: none;
  }

  div.attach-table {
    width: 400px;
  }

  div.file-title a, div.file-title a:active, div.file-title a:hover, div.file-title a:visited {
    text-decoration: none;
  }

  div.photo-title a, div.photo-title a:active, div.photo-title a:hover, div.photo-title a:visited {
    text-decoration: none;
  }

  div#ygrp-mlmsg #ygrp-msg p a span.yshortcuts {
    font-family: Verdana;
    font-size: 10px;
    font-weight: normal;
  }

  .green {
    color: #628c2a;
  }

  .MsoNormal {
    margin: 0 0 0 0;
  }

  o {
    font-size: 0;
  }

  #photos div {
    float: left;
    width: 72px;
  }

  #photos div div {
    border: 1px solid #666666;
    height: 62px;
    overflow: hidden;
    width: 62px;
  }

  #photos div label {
    color: #666666;
    font-size: 10px;
    overflow: hidden;
    text-align: center;
    white-space: nowrap;
    width: 64px;
  }

  #reco-category {
    font-size: 77%;
  }

  #reco-desc {
    font-size: 77%;
  }

  .replbq {
    margin: 4px;
  }

  #ygrp-actbar div a:first-child {
   /* border-right: 0px solid #000;*/
    margin-right: 2px;
    padding-right: 5px;
  }

  #ygrp-mlmsg {
    font-size: 13px;
    font-family: Arial, helvetica,clean, sans-serif;
    *font-size: small;
    *font: x-small;
  }

  #ygrp-mlmsg table {
    font-size: inherit;
    font: 100%;
  }

  #ygrp-mlmsg select, input, textarea {
    font: 99% Arial, Helvetica, clean, sans-serif;
  }

  #ygrp-mlmsg pre, code {
    font:115% monospace;
    *font-size:100%;
  }

  #ygrp-mlmsg * {
    line-height: 1.22em;
  }

  #ygrp-mlmsg #logo {
    padding-bottom: 10px;
  }


  #ygrp-msg p a {
    font-family: Verdana;
  }

  #ygrp-msg p#attach-count span {
    color: #1E66AE;
    font-weight: 700;
  }

  #ygrp-reco #reco-head {
    color: #ff7900;
    font-weight: 700;
  }

  #ygrp-reco {
    margin-bottom: 20px;
    padding: 0px;
  }

  #ygrp-sponsor #ov li a {
    font-size: 130%;
    text-decoration: none;
  }

  #ygrp-sponsor #ov li {
    font-size: 77%;
    list-style-type: square;
    padding: 6px 0;
  } 

  #ygrp-sponsor #ov ul {
    margin: 0;
    padding: 0 0 0 8px;
  }

  #ygrp-text {
    font-family: Georgia;
  }

  #ygrp-text p {
    margin: 0 0 1em 0;
  }

  #ygrp-text tt {
    font-size: 120%;
  }

  #ygrp-vital ul li:last-child {
    border-right: none !important; 
  } 
  -->
  </style>
</head>

<!--~-|**|PrettyHtmlEnd|**|-~-->
</html>
<!-- end group email -->


--wTvBNFFkpcYD2LRcFkK7oz5DxG4LhjVDYqmQSXT--