The anti-de Sitter/conformal field theory correspondence is a conjecture in theoretical physics that relates two kinds of physical theories. On one side of the correspondence are conformal field theories, including theories similar to the Yang–Mills theories that describe elementary particles. On the other side of the correspondence are anti-de Sitter spaces (cross section depicted), which are used in theories of quantum gravity, formulated in terms of string theory or M-theory. Proposed by Juan Maldacena in late 1997, the AdS/CFT correspondence represents a major advance in our understanding of string theory and quantum gravity. This is because it provides a non-perturbative formulation of string theory and because it is the most successful realization of the holographic principle, an idea in quantum gravity originally proposed by Gerard 't Hooft. In addition, it provides a powerful toolkit for studying strongly coupled quantum field theories and has been used to study many aspects of nuclear and condensed matter physics by translating problems in those subjects into more mathematically tractable problems in string theory.

Read more: https://en.wikipedia.org/wiki/AdS/CFT_correspondence

_______________________________ Today's selected anniversaries:

1854:

In his apostolic constitution Ineffabilis Deus, Pope Pius IX proclaimed the dogmatic definition of the Immaculate Conception, which holds that the Virgin Mary was conceived free of original sin. https://en.wikipedia.org/wiki/Immaculate_Conception

1941:

The Holocaust: The Chełmno extermination camp in occupied Poland, the first such Nazi camp to kill the Jews of the Ghetto Litzmannstadt and the Warthegau by poison gas, began operating. https://en.wikipedia.org/wiki/Che%C5%82mno_extermination_camp

1963:

After being hit by a lightning strike while in a holding pattern, Pan Am Flight 214 crashed near Elkton, Maryland, US, killing all 81 people on board. https://en.wikipedia.org/wiki/Pan_Am_Flight_214

1987:

Arab–Israeli conflict: An Israeli army tank transporter killed four Palestinian refugees and injured seven others during a traffic accident at the Erez Crossing on the Israel–Gaza Strip border, sparking the First Intifada. https://en.wikipedia.org/wiki/First_Intifada

2009:

Bombings carried out by the Islamic State of Iraq in Baghdad, Iraq, killed 127 and injured 448. https://en.wikipedia.org/wiki/December_2009_Baghdad_bombings

_____________________________ Wiktionary's word of the day:

menorah: (Judaism) A candelabrum with nine branches used in Jewish worship on Hanukkah. https://en.wiktionary.org/wiki/menorah

___________________________ Wikiquote quote of the day:

It is difficult to speak of what is common in a way of your own.    --Horace https://en.wikiquote.org/wiki/Horace