# Asymptotic charges cannot be measured in finite time

## Abstract

To study quantum gravity in asymptotically flat spacetimes, one would like to understand the algebra of observables at null infinity. Here we show that the Bondi mass cannot be observed in finite retarded time, and so is not contained in the algebra on any finite portion of I ^{+}. This follows immediately from recently discovered asymptotic entropy bounds. We verify this explicitly, and we find that attempts to measure a conserved charge at arbitrarily large radius in fixed retarded time are thwarted by quantum fluctuations. We comment on the implications of our results to flat space holography and the BMS charges at I ^{+}.

- Authors:

- Univ. of California, Berkeley, CA (United States). Center for Theoretical Physics and Dept. of Physics; Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
- Stanford Univ., CA (United States). Varian Lab. of Physics

- Publication Date:

- Research Org.:
- Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

- Sponsoring Org.:
- USDOE Office of Science (SC); Berkeley Center for Theoretical Physics (BCTP); Inst. for Advanced Study, Princeton, NJ (United States); National Science Foundation (NSF); Foundational Questions Inst. (FQXi); Raymond and Beverly Sackler Foundation; Stanford Univ., Stanford, CA (United States). Stanford Inst. for Theoretical Physics (SITP); Simons Foundation

- OSTI Identifier:
- 1423163

- Alternate Identifier(s):
- OSTI ID: 1434025

- Grant/Contract Number:
- AC02-05CH11231; 1521446; 1316783; 1314311

- Resource Type:
- Journal Article: Published Article

- Journal Name:
- Physical Review D

- Additional Journal Information:
- Journal Volume: 97; Journal Issue: 4; Related Information: © 2018 authors. Published by the American Physical Society.; Journal ID: ISSN 2470-0010

- Publisher:
- American Physical Society (APS)

- Country of Publication:
- United States

- Language:
- English

- Subject:
- 79 ASTRONOMY AND ASTROPHYSICS; 71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; general relativity; quantum gravity; quantum field theory

### Citation Formats

```
Bousso, Raphael, Chandrasekaran, Venkatesa, Halpern, Illan F., and Wall, Aron C.
```*Asymptotic charges cannot be measured in finite time*. United States: N. p., 2018.
Web. doi:10.1103/PhysRevD.97.046014.

```
Bousso, Raphael, Chandrasekaran, Venkatesa, Halpern, Illan F., & Wall, Aron C.
```*Asymptotic charges cannot be measured in finite time*. United States. doi:10.1103/PhysRevD.97.046014.

```
Bousso, Raphael, Chandrasekaran, Venkatesa, Halpern, Illan F., and Wall, Aron C. Wed .
"Asymptotic charges cannot be measured in finite time". United States.
doi:10.1103/PhysRevD.97.046014.
```

```
@article{osti_1423163,
```

title = {Asymptotic charges cannot be measured in finite time},

author = {Bousso, Raphael and Chandrasekaran, Venkatesa and Halpern, Illan F. and Wall, Aron C.},

abstractNote = {To study quantum gravity in asymptotically flat spacetimes, one would like to understand the algebra of observables at null infinity. Here we show that the Bondi mass cannot be observed in finite retarded time, and so is not contained in the algebra on any finite portion of I+. This follows immediately from recently discovered asymptotic entropy bounds. We verify this explicitly, and we find that attempts to measure a conserved charge at arbitrarily large radius in fixed retarded time are thwarted by quantum fluctuations. We comment on the implications of our results to flat space holography and the BMS charges at I+.},

doi = {10.1103/PhysRevD.97.046014},

journal = {Physical Review D},

number = 4,

volume = 97,

place = {United States},

year = {Wed Feb 28 00:00:00 EST 2018},

month = {Wed Feb 28 00:00:00 EST 2018}

}

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