Corrections to  Second Edition, 2nd revision (July 2015)   of

Student Friendly Quantum Field Theory

 

Note: 1st edition and 2nd edition (prior versions) users also need to check this 2nd edition, 2nd revision corrections page for additional corrections.

 

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Significant Corrections (may impact learning process)

 

 

Pg

Chap

Date Posted

Significant Correction

Reported by

(blank = the author)

298-299

11

June 13, 2017

(11-42) insert minus sign after 2nd equal sign. (11-44). same change (minus sign) after each equal sign.

Tom Bartholet

21,31

2

May 31, 2017

I was a bit sloppy in two blocks near the ends of Wholeness Charts 2-2 and 2-5. See corrections at Changes to Charts 2-2 and 2-5. As I noted in the text, it may be best not to get too deeply into Chart 2-2, as it is primarily a summary of classical variational mechanics, and the changes made here relate to subtle aspects of that theory, which are not so relevant for QFT.

Allan Tameshtit

239

8

May 12, 2017

First line: insert “– e” after equal sign.

Tom Bartholet

205

7

May 9, 2017

First paragraph following (7-82), “C3D4= - D3C4” should be “C3D4= - D4C3

Tom Bartholet

217

8

May 9, 2017

(8-9), after 2nd equal sign: The Sfi should be inside the Sigma and all f except that in the bra should be primed.

Tom Bartholet

231

8

May 9, 2017

(8-74) and (8-75) both need to insert “i” in front of the expression for SF

Tom Bartholet

235

8

May 9, 2017

(8-89): Insert a delta function with argument zero on the RHS outside the integral.

Tom Bartholet

61

3

May 8, 2017

Mid page, after 2nd paragraph after “Caveat”.

If normal ordering were only used in QFT to get a Delta E energy level (as that is all that is relevant in classical theory) one might concede some justification for it. However, as one will see in Chap 4 (pg. 112 after “End of Derivation”), it is also commonly invoked to get the correct charge operator for spin 1/2 fields. Otherwise, the vacuum would have an infinite charge. Since we have no theories where that can simply be subtracted, it is hard to justify use of normal ordering for charge derivation, and one’s confidence in it is further eroded.

Note that on pg. 112, I present an alternative derivation to the charge operator that does not depend on normal ordering.

 

271

10

May 8, 2017

Sect. 10.2.4. Actually, the Fulling-Davies-Unruh effect is not related to the ½ quanta, the higher order corrections, nor the 3 virtual particle bubbles, but to a more advanced concept in QFT related to time dependent Hamiltonians. Finding it in an experiment would not really be a proof of zero point energy in the usual ½ quanta sense.

 

384

15

May 8, 2017

I have recently realized that cut-off regularization has a more obvious reason for why it doesn’t work. It is not Lorentz invariant, as the upper limit on our integral (max energy) is not Lorentz invariant (energy for the same object changes as seen in different frames). The other three regularization methods discussed are all Lorentz invariant, and they all produce the correct result.

 

480

17

May 8, 2017

(17-175): the numerators should all have a “ + m” in them.

Zhang Juenjie

231

8

Jan 16, 2017

3rd line after (8-79): Change “denotes antiparticles.” to  – is sometimes used in Feynman diagrams for virtual antiparticles. It is just a symbol. The overbar here is not related to adjoint fields. –

Vasudev Godbole

211

7

Nov 11, 2016

(7-109): The first three terms on the second line should have the Nc operator in front of them.

(7-110). The last term in the top row should have the Nc operator in front.

Tom Bartholet

186

7

Oct 27, 2016

(7-19): Comparing with (7-16), one might wonder about the change in order of the QFT field operators (photon and fermion) after the equal sign. The order here is not important, as fields associated with different types of particles commute. Amu commutes with psi here.

Tom Bartholet

76

3

Sept 29, 2016

The line after (3-140). It is correct as is, but maybe easier to understand if we change “the route” to – which route (loop) -

 

198

7

Sept 22, 2016

Sentence just above Sect 7.5.2, change “(7-62)” to - (7-63) -.

Tom Bartholet

176

6

Aug 22, 2016

Eq (6-41). The first minus sign (before N_b) should be a plus sign.

Tom Bartholet

169

6

July 7, 2016

Eq. (6-14). The arguments for the vector and tensor on the RHS of their respective equal signs should not have a Lambda^alpha_beta before the x^beta. Two places. (And it might look neater to change the beta on the x to an alpha, but not essential.)

Tom Bartholet

184

7

June 22, 2016

Eq. (7-8). The minus sign in front of “e” should be a plus.

 

73

3

June 16, 2016

1st line after (3-122). The first “factor” in (3-122) is GF of (3-120). The second “factor” in (3-122) is HF of (3-120). In teaching a QFT course, I was asked by a student “where did the GF and HF of (3-120) go?”

Lou Biegeleisen

142

5

June 16, 2016

(5-35) top row. This is correct as it is, since dummy indices can be used interchangeably. However, it can be easier to understand if the mu and nu superscripts on the epsilons on the RHS of each equal signed are switched.

Tom Bartholet

142

5

June 16, 2016

(5-36). The r’s after the second equal sign should be underlined, as there is no sum.

Tom Bartholet

147

5

June 16, 2016

(5-50). The summations should only be over r, not k. The integral is over the range of k.

Tom Bartholet

247

8

June 16, 2016

2nd paragraph up from bottom of page. At end of sentence, add –  or to interactions that can be renormalized away (not treated in this text). –

 

274

10

June 16, 2016

(10-8), top row. Don’t hold up your study of QFT by spending much time on this fairly advanced material. Someday I may re-write this section with these changes. Each 1/2, should be multiplied by a delta(0), i.e., a Dirac delta function with argument zero. This also applies to every relation on the next 2-3 pages with a 1/2 term. See links on book website for Continuous Solutions for reasons why. From that one could also see why comments in this part of the text for single 1/2 quanta particle wave packet in “all space” should refer to “unit volume”.

 

281-283

10

June 16, 2016

WhCh 10-2. Wherever there is a continuous solutions form with 1/2 inside the integral, it should be a multiplied by a factor delta(0), i.e., a Dirac delta function with argument zero. See links on book website for Continuous Solutions for reasons why.

 

111

4

May 16, 2016

Sect. 4.6.3, last sentence. Change “d_r dagger” to – d_r - . Change “annihilates that state” to     – results in the vacuum |0 > -

Tom Bartholet

127

4

May 16, 2016

2nd paragraph of Conclusion #1:  Insert at beginning of paragraph: – For Fig. 4-5(b), –. After “Changing v”, insert – (without aligning it with S) – After “Therefore,”, insert – in Fig. 4-5(b) -

Tom Bartholet

158

5

May 16, 2016

Wholeness Chart 5-4, 4th row, 2nd column on page. Put a bar over rho. Two places. (rho is an expectation value not an operator here.)

Tom Bartholet

159

5

May 16, 2016

Wholeness Chart 5-4, 2nd row up from bottom on page: After “two commutators” insert - /anti-commutators -

Tom Bartholet

160

5

May 16, 2016

Wholeness Chart 5-4, top row on page: After “two commutators” insert - /anti-commutators -

Tom Bartholet

27

2

Apr 6, 2016

Eq (2-37). Some further explanation plus some changes related to (2-37) are in order. See  Comments on (2-37).

Tom Bartholet

79

3

Apr 1, 2016

In (3-150), change partial time derivative to total derivative. In next line, after “field,” insert – with the aid of Box 2.1, pg. 22, –

Tom Bartholet

74

3

Mar 2, 2016

Last line on page: After the comma, insert – we have the Cauchy integral formula -

Tom Bartholet

54

3

Aug 17, 2015

The k’s in the numerators (two places) in the second line of (3-52) should have superscripts, not subscripts. (3-52) as written, strictly speaking, is still correct, as there are two k's with subscript i multiplied, which equal two k's with superscript i multiplied. But this correction should eliminate confusion.

Steffen Leger

11

2

Aug 6, 2015

Sect. 2.1.1, point 2. After “mass”, insert - at rest -

Michael Heiss

23

2

Aug 6, 2015

Box 2-2. My purpose in this box was to give a derivation of (B2-2.3) that was much simpler than that in other books. There are some subtleties involved, but it is best not to worry about them until after you have mastered QFT. If at that time, you feel up to it, check out Box2_2_comments

 

30

2

Aug 6, 2015

For versions prior to July 2015, this was OK. For the July 2015 version, equations (2-42) and (2-43). The “i” subscript on delta would be better as a superscript. Ultimately, it doesn’t really matter, but it helps the parallel with (2-44) if “i” is superscripted.

 

 

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Minor Corrections (should not impact learning process)

 

Pg

Chap

Date Posted

Minor Correction

Reported by

285b

10

May 24, 2017

Prob. 1, 2nd line: The quantity inside the bra should not be the complex conjugate of the quantity inside the ket, but the same thing. The bra notation implies the quantity shown inside, when expressed mathematically, has the complex conjugate taken.

Tom Bartholet

282

10

May 24, 2017

Last row, 2nd column: The quantity inside the bra should not be the complex conjugate of the quantity inside the ket, but the same thing. The bra notation implies the quantity shown inside, when expressed mathematically, has the complex conjugate taken.

Tom Bartholet

285

10

May 24, 2017

Section 10.12, Appendix E: It is clearer if whenever the term “delta function“ is used, it is replaced with “Dirac delta function” (so as not to confuse with the Kronecker delta).

Tom Bartholet

256

9

May 12, 2017

Fig. 9-1, RHS: Reverse the arrow on the lower line to make it a positron.

Tom Bartholet

258

9

May 12, 2017

Box 9-1, 3rd paragraph up from bottom, 2nd line: After “x1x3x2”, insert - in (B9-1.3) -

Tom Bartholet

259

9

May 12, 2017

(9-7): It may be easier to follow if the SF(p) gamma^mu were moved to after the gamma^nu. Given that these factors are inside the trace, it doesn’t really matter, but the whole thing tracks Fig. 9-5 better if it is done this way.

Tom Bartholet

261

9

May 12, 2017

(9-13): Put a factor of 1/(2 pi)2 after the equal sign.

Tom Bartholet

262

9

May 12, 2017

Line above (9-16): After “natural” insert - and Heaviside-Lorentz -

Tom Bartholet

524

Index

May 12, 2017

After “Normal ordering, 60”, insert - 112-113 -

 

221

8

May 9, 2017

(8-24): “Bhabba” should be “Bhabha”

Tom Bartholet

224

8

May 9, 2017

(8-42), “r” subscript of “ν” should be primed

Tom Bartholet

225

8

May 9, 2017

Fig. 8-3 would probably be better with the first vertex on each side labeled x2 and the second x1, as it would track the text better. But it is common to not write in the coordinate labels at each vertex in Feynman diagrams, so the reader needs to get accustomed to the practice.

Tom Bartholet

231

8

May 9, 2017

(8-76) and (8-78): Dmu nu should be DF mu nu

Tom Bartholet

235

8

May 9, 2017

End of 1st paragraph in Sect 8.5, change “delta function” to “Dirac delta function”.

Tom Bartholet

236

8

May 9, 2017

3rd Feynman rule: iSF should be iSF (p)

Tom Bartholet

241

8

May 9, 2017

First margin note should refer to Chap. 16, not Chap. 17.

Tom Bartholet

219

8

Dec 8, 2016

This is not a correction, but an added problem.

Box 8-1. At the end of the box, add “Do Prob. 18 for more insight on this.” Then, add, at the end of the chapter.

Prob. 18. Draw the mass shell for a photon. Suppress the k2 and k3 dimensions, to make it easier. That is, plot E vs k1. Does it touch the origin? Are the sides of the shell, for a photon, straight lines? Does the mass shell for a massive particle like that shown in Box 8-1 approach that of a photon asymptotically for very high E (speed approaching c)?

Tom Bartholet

199

7

Nov 7, 2016

Sect. 7.5.3, 2nd paragraph, beginning: After “Fig. 7-1” insert - and Wholeness Chart 7-2 -

Tom Bartholet

43

3

Oct 11, 2016

Eq (3-9). May be good to insert “This is a solution given En2 - pn2 = m2”.

Jeroen Spandaw

x

 

Sept 30, 2016

Acknowledgements for 2n Ed, end of first paragraph. Move comma after “them” to after “thank”

 

2

1

Sept 30, 2016

2nd line above (1-1), delete comma at end of the line

 

127

4

Sept 30, 2016

mid page. bold 1/2 before ket should be not bold

 

131

4

Sept 30, 2016

In title of Sect 4.14.5, “The” should not be capitalized

 

264

9

Sept 30, 2016

Next to last bullet near bottom of page: delete space after “Compton”

 

144

5

Sept 23, 2016

(5-42). It will be better here if we take A^mu to be A_mu. It doesn’t matter which we use, but later in Chap 7 we do it with a subscript mu, not a superscript. So we change it here to be consistent

Tom Bartholet

184

7

Sept 22, 2016

Margin note for eq (7-6) should be - gauge - instead of “gage”

Tom Bartholet

177

6

Aug 22, 2016

In the third line of Sext 6.6.1, it is better to have the page range for 135-141 rather than 138-141.

Tom Bartholet

177

6

June 22, 2016

Top line on page: After “this means” insert - using the LHS of (6-39) - .

 

491

18

June 22, 2016

Paragraph to the right of Fig. 18-1, 3rd line: The underline marks in the argument of the delta function should just be spaces.

 

88

4

June 21, 2016

2nd paragraph up from bottom, first sentence. Exponent +/- kx should be =+/- ikx.

Lou Biegeleisen

520

19

June 21, 2016

Footnote 1. The year should be 2010, not 2002.

 

23

2

June 16, 2016

Box 2-2. Eq (B2-2.3) number not aligned.

 

143

5

June 16, 2016

Footnote paragraph is indented and shouldn’t be.

 

127

4

May 16, 2016

2nd paragraph, 2n line of Conclusion #1:  Make “1/2” not bold.

 

50

3

Mar 23, 2016

Eq. (3-37). Delete extra RH parenthesis on eq number.

Juan José Bigeón

87

4

Jan 25, 2016

3rd line from bottom of page: change “one the” to – one of the -

Pavel Fadeev

147

5

Jan 25, 2016

Sect. 5.3.1, change “pg. 155” to ‘ pg. 156 -

Pavel Fadeev

xi

Pre-face

Oct 19, 2015

7th line: after “orthodox” insert – (pedagogically) -

 

170

6

Oct 7, 2015

First margin note on page: eliminate underline on e’.

Michael Koren

51

3

Sept 10, 2015

Sect. 3.2.4, 1st line: change “of this and” to – of this chapter and –

Tom Bartholet

20

2

Sept 1, 2015

Wholeness Chart 2-2, left column, 4th row up from bottom: Change “Hamiltonian’s Equations of Motion” to -Hamilton’s Equations of Motion” -

Tom Bartholet

65

3

Aug 6, 2015

Mid page, Note on Nomenclature line: “solution” should have an - s -  on the end.

 

79

3

Aug 6, 2015

Mid page, Odds and Ends section: After “3-1” insert - (pg. 65) -. After “3-2”, insert - (pg. 68) -.

 

96

4

Aug 6, 2015

4th margin note: subscript 1 on u should not be italic

 

107

4

Aug 6, 2015

Box 4-3. Equation numbers not aligned.

 

160

5

Aug 6, 2015

4th row down in the wholeness chart, last line: Delete open parenthesis at beginning of the line.

 

166

6

Aug 6, 2015

6th line down: Change “functional” to - the function -.

 

188

7

Aug 6, 2015

Wholeness Chart 7-1. 4th row up from bottom, Operators column. Superscript S is wrong font.

 

211

7

Aug 6, 2015

1st line above (7-110): insert a comma after “them”.

 

211

7

Aug 6, 2015

(7-110), 2nd line: Boxes with 8, 9, and 10 in them should be above the terms, rather than below them.

 

463

17

Aug 6, 2015

(17-99). “1/4” font size too big.

 

371

14

Aug 6, 2015

Page heading should be “Section 14.9 Chapter Summary”. Heading as shown should have “mu” instead of a box (2 places). Computer glitch in 2nd ed. Not in 1st.

 

508

18

Aug 6, 2015

Wholeness Chart 18-6. Title needs to be centered

 

 

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