# Cosmological Constant from Boundary Condition and Its Implications beyond the Standard Model

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## Abstract

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## 1. Introduction

## 2. Why the Metric Needs to Be Constrained by a Boundary Condition

## 3. Scale Factor as a Function of Distance

#### 3.1. Measures of Time and Distance

#### 3.2. Interpretation of Redshift Observations

#### 3.3. Meaning of the Hubble Constant

## 4. Derivation of the Value for $\mathsf{\Lambda}$

#### 4.1. Spatial Perturbations of the FLRW Metric

#### 4.2. Solution of the Einstein Equation in the Presence of Spatial Perturbations

#### 4.3. Restriction to the Light Cone

#### 4.4. Implementation of the Spatial Boundary Condition to Obtain the Value for $\mathsf{\Lambda}$

#### 4.5. Observational Validation

## 5. Implications beyond the Standard Model

#### 5.1. Age of the Universe

#### 5.2. ${H}_{0}$ Tension

## 6. Conclusions

## Funding

## Data Availability Statement

## Acknowledgments

## Conflicts of Interest

## References

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**MDPI and ACS Style**

Stenflo, J.O.
Cosmological Constant from Boundary Condition and Its Implications beyond the Standard Model. *Universe* **2023**, *9*, 103.
https://doi.org/10.3390/universe9020103

**AMA Style**

Stenflo JO.
Cosmological Constant from Boundary Condition and Its Implications beyond the Standard Model. *Universe*. 2023; 9(2):103.
https://doi.org/10.3390/universe9020103

**Chicago/Turabian Style**

Stenflo, Jan O.
2023. "Cosmological Constant from Boundary Condition and Its Implications beyond the Standard Model" *Universe* 9, no. 2: 103.
https://doi.org/10.3390/universe9020103