title: Reason for the exponential speed-up expected from quantum computers
body: <p>In quantum computers those 2 effects should be seen:</p>
  
  <p>1) If an operator acts on an arbitrary QuBit Qn of a quantum system S consisting of several QuBits than we get a new quantum system S' where the amplitues of ALL QuBits have changed.</p>
  
  <p>2) If an operator acts on one QuBit of a quantum system T consisting of two entangled QuBits than both QuBits are affected.</p>
  
  <p>So which one of these is the reason for the exponential speed-up expected from quantum computers?</p>