High Quality Content by WIKIPEDIA articles! High Quality Content by WIKIPEDIA articles! In physics, spontaneous symmetry breaking occurs when a system that is symmetric with respect to some symmetry group goes into a vacuum state that is not symmetric When that happens, the system no longer appears to behave in a symmetric manner It is a phenomenon озозв that naturally occurs in many situations The symmetry group can be discrete, such as the space group of a crystal, or continuous, such as the rotational symmetry of space However if the system contains only a single spatial dimension then only discrete symmetries may be broken in a vacuum state of the full quantum theory, although a classical solution may break a continuous symmetry.  Planter2010 г Мягкая обложка, 92 стр ISBN 6130351348.