scholarly journals Quantum gravity and the cosmological constant: Lessons from two-dimensional dilaton gravity

2013 ◽  
Vol 87 (8) ◽  
Author(s):  
Jan Govaerts ◽  
Simone Zonetti
Keyword(s):  
Quantum Gravity ◽  
Cosmological Constant ◽  
Two Dimensional ◽  
Dilaton Gravity

THE APPEARANCE OF MATTER FIELDS FROM QUANTUM FLUCTUATIONS OF 2D-GRAVITY

1989 ◽  
Vol 04 (22) ◽  
pp. 2125-2139 ◽  
Author(s):  
V.A. KAZAKOV
Keyword(s):  
Quantum Gravity ◽  
Cosmological Constant ◽  
Critical Exponent ◽  
2D Gravity ◽  
Central Charge ◽  
Quantum Fluctuations ◽  
Two Dimensional ◽  
Conformal Fields ◽  
Exactly Solvable ◽  
Matter Fields

It is established that various critical regimes may occur for a model of two-dimensional pure quantum gravity. These regimes correspond to the presence of effective fields with scaling dimensions Δk=−γ str ·k/2, k=1, 2, 3 ..., where γ str =−1/m, m=2, 3, 4 ... is the critical exponent of “string susceptibility” (with respect to the cosmological constant). This behaviour is typical for unitary conformal fields with the central charge c=1−6/m(m+1) in the presence of 2D-quantum gravity. We use the framework of loop equations for the invariant boundary functional, which are exactly solvable in this case.

scholarly journals The two-sphere partition function in two-dimensional quantum gravity

2021 ◽  
Vol 2021 (9) ◽  
Author(s):  
Dionysios Anninos ◽  
Teresa Bautista ◽  
Beatrix Mühlmann
Keyword(s):  
Partition Function ◽  
Quantum Gravity ◽  
Cosmological Constant ◽  
Path Integral ◽  
Central Charge ◽  
Liouville Theory ◽  
Two Dimensional ◽  
Positive Cosmological Constant ◽  
Gauge Fixing ◽  
Semiclassical Expansion

Abstract We study the Euclidean path integral of two-dimensional quantum gravity with positive cosmological constant coupled to conformal matter with large and positive central charge. The problem is considered in a semiclassical expansion about a round two-sphere saddle. We work in the Weyl gauge whereby the computation reduces to that for a (timelike) Liouville theory. We present results up to two-loops, including a discussion of contributions stemming from the gauge fixing procedure. We exhibit cancelations of ultraviolet divergences and provide a path integral computation of the central charge for timelike Liouville theory. Combining our analysis with insights from the DOZZ formula we are led to a proposal for an all orders result for the two-dimensional gravitational partition function on the two-sphere.

scholarly journals Two-dimensional dilaton gravity theory and lattice Schwarzian theory

2019 ◽  
Vol 34 (29) ◽  
pp. 1950176
Author(s):  
Su-Kuan Chu ◽  
Chen-Te Ma ◽  
Chih-Hung Wu
Keyword(s):  
Boundary Condition ◽  
Cosmological Constant ◽  
Dirichlet Boundary Condition ◽  
Dirichlet Boundary ◽  
Gravity Theory ◽  
Boundary Theory ◽  
Two Dimensional ◽  
Dilaton Field ◽  
Dilaton Gravity ◽  
Cosmological Constants

We report a holographic study of a two-dimensional dilaton gravity theory with the Dirichlet boundary condition for the cases of nonvanishing and vanishing cosmological constants. Our result shows that the boundary theory of the two-dimensional dilaton gravity theory with the Dirichlet boundary condition for the case of nonvanishing cosmological constants is the Schwarzian term coupled to a dilaton field, while for the case of vanishing cosmological constant, a theory does not have a kinetic term. We also include the higher derivative term [Formula: see text], where [Formula: see text] is the scalar curvature that is coupled to a dilaton field. We find that the form of the boundary theory is not modified perturbatively. Finally, we show that a lattice holographic picture is realized up to the second-order perturbation of boundary cutoff [Formula: see text] under a constant boundary dilaton field and the nonvanishing cosmological constant by identifying the lattice spacing [Formula: see text] of a lattice Schwarzian theory with the boundary cutoff [Formula: see text] of the two-dimensional dilaton gravity theory.

scholarly journals IRREVERSIBLE TIME FLOW IN A TWO-DIMENSIONAL DILATON BLACK HOLE WITH MATTER

1998 ◽  
Vol 13 (24) ◽  
pp. 4265-4279 ◽  
Author(s):  
G. A. DIAMANDIS ◽  
B. C. GEORGALAS ◽  
N. E. MAVROMATOS ◽  
JOHN ELLIS ◽  
D. V. NANOPOULOS ◽  
...  
Keyword(s):  
Cosmological Constant ◽  
Flat Space ◽  
Back Reaction ◽  
Two Dimensional ◽  
Dilaton Gravity ◽  
Renormalization Group Flow ◽  
Target Time ◽  
Time Flow ◽  
Group Flow ◽  
Temporal Flow

We show that an exact solution of two-dimensional dilaton gravity with matter discovered previously exhibits an irreversible temporal flow towards flat space with a vanishing cosmological constant. This time flow is induced by the back reaction of matter on the space–time geometry. We demonstrate that the system is not in equilibrium if the cosmological constant is nonzero, whereas the solution with zero cosmological constant is stable. The flow of the system towards this stable end point is derived from the renormalization-group flow of the Zamolodchikov function. This behavior is interpreted in terms of noncritical Liouville string, with the Liouville field identified as the target time.

scholarly journals MEASUREMENTS AND INFORMATION IN SPIN FOAM MODELS

2012 ◽  
Vol 27 (28) ◽  
pp. 1250164
Author(s):  
J. MANUEL GARCÍA-ISLAS
Keyword(s):  
Information Theory ◽  
Quantum Gravity ◽  
Cosmological Constant ◽  
Shannon Entropy ◽  
Three Dimensional ◽  
Spin Network ◽  
Spin Foam Models ◽  
Foam Model ◽  
Spin Foam Model ◽  
Spin Foam

In the three-dimensional spin foam model of quantum gravity with a cosmological constant, there exists a set of observables associated with spin network graphs. A set of probabilities is calculated from these observables, and hence the associated Shannon entropy can be defined. We present the Shannon entropy associated with these observables and find some interesting bounded inequalities. The problem relates measurements, entropy and information theory in a simple way which we explain.

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